CVE-2026-23352
published 2026-03-25CVE-2026-23352: In the Linux kernel, the following vulnerability has been resolved: x86/efi: defer freeing of boot services memory efi_free_boot_services() frees memory…
PriorityP420medium5.5CVSS 3.1
AVLACLPRLUINSUCNINAH
EPSS
0.13%
2.6th percentile
In the Linux kernel, the following vulnerability has been resolved:
x86/efi: defer freeing of boot services memory
efi_free_boot_services() frees memory occupied by EFI_BOOT_SERVICES_CODE
and EFI_BOOT_SERVICES_DATA using memblock_free_late().
There are two issue with that: memblock_free_late() should be used for
memory allocated with memblock_alloc() while the memory reserved with
memblock_reserve() should be freed with free_reserved_area().
More acutely, with CONFIG_DEFERRED_STRUCT_PAGE_INIT=y
efi_free_boot_services() is called before deferred initialization of the
memory map is complete.
Benjamin Herrenschmidt reports that this causes a leak of ~140MB of
RAM on EC2 t3a.nano instances which only have 512MB or RAM.
If the freed memory resides in the areas that memory map for them is
still uninitialized, they won't be actually freed because
memblock_free_late() calls memblock_free_pages() and the latter skips
uninitialized pages.
Using free_reserved_area() at this point is also problematic because
__free_page() accesses the buddy of the freed page and that again might
end up in uninitialized part of the memory map.
Delaying the entire efi_free_boot_services() could be problematic
because in addition to freeing boot services memory it updates
efi.memmap without any synchronization and that's undesirable late in
boot when there is concurrency.
More robust approach is to only defer freeing of the EFI boot services
memory.
Split efi_free_boot_services() in two. First efi_unmap_boot_services()
collects ranges that should be freed into an array then
efi_free_boot_services() later frees them after deferred init is complete.
Affected
67 ranges· showing 25
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | linux | < linux 6.19.8-1 (forky) | linux 6.19.8-1 (forky) |
| linux | linux | — | — |
| linux | linux | >= 0aed459e8487eb6ebdb4efe8cefe1eafbc704b30 < 4a2cb90c538f06c873a187aa743575d48685d7a6 | 4a2cb90c538f06c873a187aa743575d48685d7a6 |
| linux | linux | >= 2.6.39.1 < 2.6.39.2 | 2.6.39.2 |
| linux | linux | >= 916f676f8dc016103f983c7ec54c18ecdbb6e349 < 7131bd1fecc749bc94fb44aae217bbd8a8a85264 | 7131bd1fecc749bc94fb44aae217bbd8a8a85264 |
| linux | linux | >= 916f676f8dc016103f983c7ec54c18ecdbb6e349 < 6d8ba221e7aafaa2f284b7d22faee814c28e009d | 6d8ba221e7aafaa2f284b7d22faee814c28e009d |
| linux | linux | >= 916f676f8dc016103f983c7ec54c18ecdbb6e349 < 227688312fece0026fc67a00ba9a0b3611ebe95d | 227688312fece0026fc67a00ba9a0b3611ebe95d |
| linux | linux | >= 916f676f8dc016103f983c7ec54c18ecdbb6e349 < 6a25e25279282c5c8ade554c04c6ab9dc7902c64 | 6a25e25279282c5c8ade554c04c6ab9dc7902c64 |
| linux | linux | >= 916f676f8dc016103f983c7ec54c18ecdbb6e349 < 399da820ecfe6f4f10c143e5c453d3559a04db9c | 399da820ecfe6f4f10c143e5c453d3559a04db9c |
| linux | linux | >= 916f676f8dc016103f983c7ec54c18ecdbb6e349 < f9e9cc320854a76a39e7bc92d144554f3a727fad | f9e9cc320854a76a39e7bc92d144554f3a727fad |
| linux | linux | >= 916f676f8dc016103f983c7ec54c18ecdbb6e349 < 7dcf59422a3b0d20ddda844f856b4a1e0608a326 | 7dcf59422a3b0d20ddda844f856b4a1e0608a326 |
| linux | linux | >= 916f676f8dc016103f983c7ec54c18ecdbb6e349 < a4b0bf6a40f3c107c67a24fbc614510ef5719980 | a4b0bf6a40f3c107c67a24fbc614510ef5719980 |
| linux | linux_kernel | — | — |
| linux | linux_kernel | — | — |
| linux | linux_kernel | — | — |
| linux | linux_kernel | >= 0 < 6.19.8-1 | 6.19.8-1 |
| linux | linux_kernel | >= 0 < 2.6.39.2 | 2.6.39.2 |
| linux | linux_kernel | >= 2.7.0 < 6.1.167 | 6.1.167 |
| linux | linux_kernel | >= 3.0.0 < 6.6.130 | 6.6.130 |
| linux | linux_kernel | >= 3.0.1 < 5.10.253 | 5.10.253 |
| linux | linux_kernel | >= 5.11 < 5.15.203 | 5.15.203 |
| linux | linux_kernel | >= 5.16 < 6.1.167 | 6.1.167 |
| linux | linux_kernel | >= 6.13 < 6.18.17 | 6.18.17 |
| linux | linux_kernel | >= 6.13.0 < 6.19.7 | 6.19.7 |
| linux | linux_kernel | >= 6.19 < 6.19.7 | 6.19.7 |
CVSS provenance
nvdv3.15.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
vendor_msrc7.1HIGH
vendor_ubuntu7.1HIGH
vendor_redhat5.5LOW
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Ubuntu
Linux kernel vulnerabilities
vendor_ubuntu·2026-07-28·CVSS 7.1
CVE-2024-36898 [HIGH] Linux kernel vulnerabilities
Title: Linux kernel vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
Maxim Suhanov discovered that the NTFS file system implementation in the
Linux kernel did not properly validate file name length in certain
situations, leading to an out-of-bounds read. An attacker could use this to
construct a malicious NTFS image that, when mounted and operated on, could
expose sensitive information (kernel memory). (CVE-2023-45896)
It was discovered that some AMD processors did not properly clear data in
the floating point divider unit during speculative execution. A local
attacker could use this to expose sensitive information. (CVE-2025-54505)
It was discovered that some AMD Zen 2 processors did not properly isolate
shared resources in the operation cache. A local
Ubuntu
Linux kernel (HWE) vulnerabilities
vendor_ubuntu·2026-07-28·CVSS 2.0
CVE-2026-46073 [LOW] Linux kernel (HWE) vulnerabilities
Title: Linux kernel (HWE) vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
It was discovered that some AMD processors did not properly clear data in
the floating point divider unit during speculative execution. A local
attacker could use this to expose sensitive information. (CVE-2025-54505)
It was discovered that some AMD Zen 2 processors did not properly isolate
shared resources in the operation cache. A local attacker could possibly
use this issue to corrupt instructions executed at a higher privilege
level, resulting in privilege escalation. (CVE-2025-54518)
It was discovered that some AMD Zen 5 processors supporting RDSEED
instruction did not properly handle entropy, potentially resulting in the
consumption of insufficiently random values. A local a
Ubuntu
Linux kernel (Azure CVM) vulnerabilities
vendor_ubuntu·2026-07-24·CVSS 2.0
CVE-2026-46073 [LOW] Linux kernel (Azure CVM) vulnerabilities
Title: Linux kernel (Azure CVM) vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
It was discovered that some AMD processors did not properly clear data in
the floating point divider unit during speculative execution. A local
attacker could use this to expose sensitive information. (CVE-2025-54505)
It was discovered that some AMD Zen 2 processors did not properly isolate
shared resources in the operation cache. A local attacker could possibly
use this issue to corrupt instructions executed at a higher privilege
level, resulting in privilege escalation. (CVE-2025-54518)
It was discovered that some AMD Zen 5 processors supporting RDSEED
instruction did not properly handle entropy, potentially resulting in the
consumption of insufficiently random values. A l
Ubuntu
Linux kernel (Azure FIPS) vulnerabilities
vendor_ubuntu·2026-07-24·CVSS 2.0
CVE-2026-46073 [LOW] Linux kernel (Azure FIPS) vulnerabilities
Title: Linux kernel (Azure FIPS) vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
It was discovered that some AMD processors did not properly clear data in
the floating point divider unit during speculative execution. A local
attacker could use this to expose sensitive information. (CVE-2025-54505)
It was discovered that some AMD Zen 2 processors did not properly isolate
shared resources in the operation cache. A local attacker could possibly
use this issue to corrupt instructions executed at a higher privilege
level, resulting in privilege escalation. (CVE-2025-54518)
It was discovered that some AMD Zen 5 processors supporting RDSEED
instruction did not properly handle entropy, potentially resulting in the
consumption of insufficiently random values. A
Ubuntu
Linux kernel (Azure CVM) vulnerabilities
vendor_ubuntu·2026-07-24·CVSS 2.0
CVE-2026-43129 [LOW] Linux kernel (Azure CVM) vulnerabilities
Title: Linux kernel (Azure CVM) vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
It was discovered that some AMD processors did not properly clear data in
the floating point divider unit during speculative execution. A local
attacker could use this to expose sensitive information. (CVE-2025-54505)
It was discovered that some AMD Zen 2 processors did not properly isolate
shared resources in the operation cache. A local attacker could possibly
use this issue to corrupt instructions executed at a higher privilege
level, resulting in privilege escalation. (CVE-2025-54518)
It was discovered that some AMD Zen 5 processors supporting RDSEED
instruction did not properly handle entropy, potentially resulting in the
consumption of insufficiently random values. A l
Ubuntu
Linux kernel (Azure CVM) vulnerabilities
vendor_ubuntu·2026-07-24·CVSS 7.1
CVE-2024-36898 [HIGH] Linux kernel (Azure CVM) vulnerabilities
Title: Linux kernel (Azure CVM) vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
Maxim Suhanov discovered that the NTFS file system implementation in the
Linux kernel did not properly validate file name length in certain
situations, leading to an out-of-bounds read. An attacker could use this to
construct a malicious NTFS image that, when mounted and operated on, could
expose sensitive information (kernel memory). (CVE-2023-45896)
It was discovered that some AMD processors did not properly clear data in
the floating point divider unit during speculative execution. A local
attacker could use this to expose sensitive information. (CVE-2025-54505)
It was discovered that some AMD Zen 2 processors did not properly isolate
shared resources in the operation cac
Ubuntu
Linux kernel (Azure) vulnerabilities
vendor_ubuntu·2026-07-24·CVSS 2.0
CVE-2026-46073 [LOW] Linux kernel (Azure) vulnerabilities
Title: Linux kernel (Azure) vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
It was discovered that some AMD processors did not properly clear data in
the floating point divider unit during speculative execution. A local
attacker could use this to expose sensitive information. (CVE-2025-54505)
It was discovered that some AMD Zen 2 processors did not properly isolate
shared resources in the operation cache. A local attacker could possibly
use this issue to corrupt instructions executed at a higher privilege
level, resulting in privilege escalation. (CVE-2025-54518)
It was discovered that some AMD Zen 5 processors supporting RDSEED
instruction did not properly handle entropy, potentially resulting in the
consumption of insufficiently random values. A local
Ubuntu
Linux kernel (AWS) vulnerabilities
vendor_ubuntu·2026-07-24·CVSS 2.0
CVE-2026-46073 [LOW] Linux kernel (AWS) vulnerabilities
Title: Linux kernel (AWS) vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
It was discovered that some AMD processors did not properly clear data in
the floating point divider unit during speculative execution. A local
attacker could use this to expose sensitive information. (CVE-2025-54505)
It was discovered that some AMD Zen 2 processors did not properly isolate
shared resources in the operation cache. A local attacker could possibly
use this issue to corrupt instructions executed at a higher privilege
level, resulting in privilege escalation. (CVE-2025-54518)
It was discovered that some AMD Zen 5 processors supporting RDSEED
instruction did not properly handle entropy, potentially resulting in the
consumption of insufficiently random values. A local a
Ubuntu
Linux kernel (Oracle) vulnerabilities
vendor_ubuntu·2026-07-23·CVSS 2.0
CVE-2026-46073 [LOW] Linux kernel (Oracle) vulnerabilities
Title: Linux kernel (Oracle) vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
It was discovered that some AMD processors did not properly clear data in
the floating point divider unit during speculative execution. A local
attacker could use this to expose sensitive information. (CVE-2025-54505)
It was discovered that some AMD Zen 2 processors did not properly isolate
shared resources in the operation cache. A local attacker could possibly
use this issue to corrupt instructions executed at a higher privilege
level, resulting in privilege escalation. (CVE-2025-54518)
It was discovered that some AMD Zen 5 processors supporting RDSEED
instruction did not properly handle entropy, potentially resulting in the
consumption of insufficiently random values. A loca
Ubuntu
Linux kernel (NVIDIA) vulnerabilities
vendor_ubuntu·2026-07-23·CVSS 2.0
CVE-2026-43129 [LOW] Linux kernel (NVIDIA) vulnerabilities
Title: Linux kernel (NVIDIA) vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
It was discovered that some AMD processors did not properly clear data in
the floating point divider unit during speculative execution. A local
attacker could use this to expose sensitive information. (CVE-2025-54505)
It was discovered that some AMD Zen 2 processors did not properly isolate
shared resources in the operation cache. A local attacker could possibly
use this issue to corrupt instructions executed at a higher privilege
level, resulting in privilege escalation. (CVE-2025-54518)
It was discovered that some AMD Zen 5 processors supporting RDSEED
instruction did not properly handle entropy, potentially resulting in the
consumption of insufficiently random values. A loca
Ubuntu
Linux kernel (IBM) vulnerabilities
vendor_ubuntu·2026-07-23·CVSS 7.1
CVE-2026-46187 [HIGH] Linux kernel (IBM) vulnerabilities
Title: Linux kernel (IBM) vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
Maxim Suhanov discovered that the NTFS file system implementation in the
Linux kernel did not properly validate file name length in certain
situations, leading to an out-of-bounds read. An attacker could use this to
construct a malicious NTFS image that, when mounted and operated on, could
expose sensitive information (kernel memory). (CVE-2023-45896)
It was discovered that some AMD processors did not properly clear data in
the floating point divider unit during speculative execution. A local
attacker could use this to expose sensitive information. (CVE-2025-54505)
It was discovered that some AMD Zen 2 processors did not properly isolate
shared resources in the operation cache. A
Ubuntu
Linux kernel vulnerabilities
vendor_ubuntu·2026-07-23·CVSS 7.1
CVE-2026-46187 [HIGH] Linux kernel vulnerabilities
Title: Linux kernel vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
Maxim Suhanov discovered that the NTFS file system implementation in the
Linux kernel did not properly validate file name length in certain
situations, leading to an out-of-bounds read. An attacker could use this to
construct a malicious NTFS image that, when mounted and operated on, could
expose sensitive information (kernel memory). (CVE-2023-45896)
It was discovered that some AMD processors did not properly clear data in
the floating point divider unit during speculative execution. A local
attacker could use this to expose sensitive information. (CVE-2025-54505)
It was discovered that some AMD Zen 2 processors did not properly isolate
shared resources in the operation cache. A local
Ubuntu
Linux kernel (NVIDIA Tegra) vulnerabilities
vendor_ubuntu·2026-07-23·CVSS 7.1
CVE-2026-46187 [HIGH] Linux kernel (NVIDIA Tegra) vulnerabilities
Title: Linux kernel (NVIDIA Tegra) vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
Maxim Suhanov discovered that the NTFS file system implementation in the
Linux kernel did not properly validate file name length in certain
situations, leading to an out-of-bounds read. An attacker could use this to
construct a malicious NTFS image that, when mounted and operated on, could
expose sensitive information (kernel memory). (CVE-2023-45896)
It was discovered that some AMD processors did not properly clear data in
the floating point divider unit during speculative execution. A local
attacker could use this to expose sensitive information. (CVE-2025-54505)
It was discovered that some AMD Zen 2 processors did not properly isolate
shared resources in the operation
Ubuntu
Linux kernel vulnerabilities
vendor_ubuntu·2026-07-23·CVSS 2.0
CVE-2026-46073 [LOW] Linux kernel vulnerabilities
Title: Linux kernel vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
It was discovered that some AMD processors did not properly clear data in
the floating point divider unit during speculative execution. A local
attacker could use this to expose sensitive information. (CVE-2025-54505)
It was discovered that some AMD Zen 2 processors did not properly isolate
shared resources in the operation cache. A local attacker could possibly
use this issue to corrupt instructions executed at a higher privilege
level, resulting in privilege escalation. (CVE-2025-54518)
It was discovered that some AMD Zen 5 processors supporting RDSEED
instruction did not properly handle entropy, potentially resulting in the
consumption of insufficiently random values. A local attacke
Ubuntu
Linux kernel (GCP FIPS) vulnerabilities
vendor_ubuntu·2026-07-21·CVSS 2.0
CVE-2026-46073 [LOW] Linux kernel (GCP FIPS) vulnerabilities
Title: Linux kernel (GCP FIPS) vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
It was discovered that some AMD processors did not properly clear data in
the floating point divider unit during speculative execution. A local
attacker could use this to expose sensitive information. (CVE-2025-54505)
It was discovered that some AMD Zen 2 processors did not properly isolate
shared resources in the operation cache. A local attacker could possibly
use this issue to corrupt instructions executed at a higher privilege
level, resulting in privilege escalation. (CVE-2025-54518)
It was discovered that some AMD Zen 5 processors supporting RDSEED
instruction did not properly handle entropy, potentially resulting in the
consumption of insufficiently random values. A lo
Ubuntu
Linux kernel vulnerabilities
vendor_ubuntu·2026-07-21·CVSS 7.1
CVE-2024-36898 [HIGH] Linux kernel vulnerabilities
Title: Linux kernel vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
Maxim Suhanov discovered that the NTFS file system implementation in the
Linux kernel did not properly validate file name length in certain
situations, leading to an out-of-bounds read. An attacker could use this to
construct a malicious NTFS image that, when mounted and operated on, could
expose sensitive information (kernel memory). (CVE-2023-45896)
It was discovered that some AMD processors did not properly clear data in
the floating point divider unit during speculative execution. A local
attacker could use this to expose sensitive information. (CVE-2025-54505)
It was discovered that some AMD Zen 2 processors did not properly isolate
shared resources in the operation cache. A local
Ubuntu
Linux kernel (NVIDIA Tegra) vulnerabilities
vendor_ubuntu·2026-07-21·CVSS 7.1
CVE-2024-36898 [HIGH] Linux kernel (NVIDIA Tegra) vulnerabilities
Title: Linux kernel (NVIDIA Tegra) vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
Maxim Suhanov discovered that the NTFS file system implementation in the
Linux kernel did not properly validate file name length in certain
situations, leading to an out-of-bounds read. An attacker could use this to
construct a malicious NTFS image that, when mounted and operated on, could
expose sensitive information (kernel memory). (CVE-2023-45896)
It was discovered that some AMD processors did not properly clear data in
the floating point divider unit during speculative execution. A local
attacker could use this to expose sensitive information. (CVE-2025-54505)
It was discovered that some AMD Zen 2 processors did not properly isolate
shared resources in the operation
Ubuntu
Linux kernel vulnerabilities
vendor_ubuntu·2026-07-20·CVSS 2.0
CVE-2026-46073 [LOW] Linux kernel vulnerabilities
Title: Linux kernel vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
It was discovered that some AMD processors did not properly clear data in
the floating point divider unit during speculative execution. A local
attacker could use this to expose sensitive information. (CVE-2025-54505)
It was discovered that some AMD Zen 2 processors did not properly isolate
shared resources in the operation cache. A local attacker could possibly
use this issue to corrupt instructions executed at a higher privilege
level, resulting in privilege escalation. (CVE-2025-54518)
It was discovered that some AMD Zen 5 processors supporting RDSEED
instruction did not properly handle entropy, potentially resulting in the
consumption of insufficiently random values. A local attacke
Red Hat
kernel: x86/efi: defer freeing of boot services memory
vendor_redhat·2026-03-25·CVSS 5.5
CVE-2026-23352 [LOW] CWE-763 kernel: x86/efi: defer freeing of boot services memory
kernel: x86/efi: defer freeing of boot services memory
In the Linux kernel, the following vulnerability has been resolved:
x86/efi: defer freeing of boot services memory
efi_free_boot_services() frees memory occupied by EFI_BOOT_SERVICES_CODE
and EFI_BOOT_SERVICES_DATA using memblock_free_late().
There are two issue with that: memblock_free_late() should be used for
memory allocated with memblock_alloc() while the memory reserved with
memblock_reserve() should be freed with free_reserved_area().
More acutely, with CONFIG_DEFERRED_STRUCT_PAGE_INIT=y
efi_free_boot_services() is called before deferred initialization of the
memory map is complete.
Benjamin Herrenschmidt reports that this causes a leak of ~140MB of
RAM on EC2 t3a.nano instances which only have 512MB or RAM.
If the freed memory
Microsoft
x86/efi: defer freeing of boot services memory
vendor_msrc·2026-03-10·CVSS 7.1
CVE-2026-23352 [HIGH] x86/efi: defer freeing of boot services memory
x86/efi: defer freeing of boot services memory
Mariner: Mariner
Linux: Linux
Customer Action Required: Yes
Remediation: CBL-Mariner Releases
Reference: https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade
Debian
CVE-2026-23352: linux - In the Linux kernel, the following vulnerability has been resolved: x86/efi: de...
vendor_debian·2026
CVE-2026-23352 CVE-2026-23352: linux - In the Linux kernel, the following vulnerability has been resolved: x86/efi: de...
In the Linux kernel, the following vulnerability has been resolved: x86/efi: defer freeing of boot services memory efi_free_boot_services() frees memory occupied by EFI_BOOT_SERVICES_CODE and EFI_BOOT_SERVICES_DATA using memblock_free_late(). There are two issue with that: memblock_free_late() should be used for memory allocated with memblock_alloc() while the memory reserved with memblock_reserve() should be freed with free_reserved_area(). More acutely, with CONFIG_DEFERRED_STRUCT_PAGE_INIT=y efi_free_boot_services() is called before deferred initialization of the memory map is complete. Benjamin Herrenschmidt reports that this causes a leak of ~140MB of RAM on EC2 t3a.nano instances which only have 512MB or RAM. If the freed memory resides in the areas that memory map for them is still
VulDB
Linux Kernel up to 7.0-rc2 EFI Boot Service efi_free_boot_services initialization (Nessus ID 311783)
vuldb·2026-05-04·CVSS 5.5
CVE-2026-23352 [MEDIUM] Linux Kernel up to 7.0-rc2 EFI Boot Service efi_free_boot_services initialization (Nessus ID 311783)
A vulnerability was found in Linux Kernel up to 7.0-rc2. It has been declared as critical. This affects the function efi_free_boot_services of the component EFI Boot Service. Executing a manipulation can lead to improper initialization.
This vulnerability is handled as CVE-2026-23352. The attack can only be done within the local network. There is not any exploit available.
It is recommended to upgrade the affected component.
GHSA
GHSA-3ggx-9863-fxcm: In the Linux kernel, the following vulnerability has been resolved:
x86/efi: defer freeing of boot services memory
efi_free_boot_services() frees me
ghsa_unreviewed·2026-03-25
CVE-2026-23352 GHSA-3ggx-9863-fxcm: In the Linux kernel, the following vulnerability has been resolved:
x86/efi: defer freeing of boot services memory
efi_free_boot_services() frees me
In the Linux kernel, the following vulnerability has been resolved:
x86/efi: defer freeing of boot services memory
efi_free_boot_services() frees memory occupied by EFI_BOOT_SERVICES_CODE
and EFI_BOOT_SERVICES_DATA using memblock_free_late().
There are two issue with that: memblock_free_late() should be used for
memory allocated with memblock_alloc() while the memory reserved with
memblock_reserve() should be freed with free_reserved_area().
More acutely, with CONFIG_DEFERRED_STRUCT_PAGE_INIT=y
efi_free_boot_services() is called before deferred initialization of the
memory map is complete.
Benjamin Herrenschmidt reports that this causes a leak of ~140MB of
RAM on EC2 t3a.nano instances which only have 512MB or RAM.
If the freed memory resides in the areas that memory map for them is
OSV
CVE-2026-23352: In the Linux kernel, the following vulnerability has been resolved: x86/efi: defer freeing of boot services memory efi_free_boot_services() frees memo
osv·2026-03-25
CVE-2026-23352 CVE-2026-23352: In the Linux kernel, the following vulnerability has been resolved: x86/efi: defer freeing of boot services memory efi_free_boot_services() frees memo
In the Linux kernel, the following vulnerability has been resolved: x86/efi: defer freeing of boot services memory efi_free_boot_services() frees memory occupied by EFI_BOOT_SERVICES_CODE and EFI_BOOT_SERVICES_DATA using memblock_free_late(). There are two issue with that: memblock_free_late() should be used for memory allocated with memblock_alloc() while the memory reserved with memblock_reserve() should be freed with free_reserved_area(). More acutely, with CONFIG_DEFERRED_STRUCT_PAGE_INIT=y efi_free_boot_services() is called before deferred initialization of the memory map is complete. Benjamin Herrenschmidt reports that this causes a leak of ~140MB of RAM on EC2 t3a.nano instances which only have 512MB or RAM. If the freed memory resides in the areas that memory map for them is still
OSV
x86/efi: defer freeing of boot services memory
osv·2026-03-25
CVE-2026-23352 x86/efi: defer freeing of boot services memory
x86/efi: defer freeing of boot services memory
In the Linux kernel, the following vulnerability has been resolved:
x86/efi: defer freeing of boot services memory
efi_free_boot_services() frees memory occupied by EFI_BOOT_SERVICES_CODE
and EFI_BOOT_SERVICES_DATA using memblock_free_late().
There are two issue with that: memblock_free_late() should be used for
memory allocated with memblock_alloc() while the memory reserved with
memblock_reserve() should be freed with free_reserved_area().
More acutely, with CONFIG_DEFERRED_STRUCT_PAGE_INIT=y
efi_free_boot_services() is called before deferred initialization of the
memory map is complete.
Benjamin Herrenschmidt reports that this causes a leak of ~140MB of
RAM on EC2 t3a.nano instances which only have 512MB or RAM.
If the freed memory r
No detection rules found.
No public exploits indexed.
Wiz
CVE-2026-23352 Impact, Exploitability, and Mitigation Steps | Wiz
blogs_wiz
CVE-2026-23352 CVE-2026-23352 Impact, Exploitability, and Mitigation Steps | Wiz
## CVE-2026-23352 :
Linux Kernel vulnerability analysis and mitigation
In the Linux kernel, the following vulnerability has been resolved:
x86/efi: defer freeing of boot services memory
efi_free_boot_services() frees memory occupied by EFI_BOOT_SERVICES_CODE
and EFI_BOOT_SERVICES_DATA using memblock_free_late().
There are two issue with that: memblock_free_late() should be used for
memory allocated with memblock_alloc() while the memory reserved with
memblock_reserve() should be freed with free_reserved_area().
More acutely, with CONFIG_DEFERRED_STRUCT_PAGE_INIT=y
efi_free_boot_services() is called before deferred initialization of the
memory map is complete.
Benjamin Herrenschmidt reports that this causes a leak of ~140MB of
RAM on EC2 t3a.nano instances which only have 512MB or RA
Bugzilla
CVE-2026-23352 kernel: x86/efi: defer freeing of boot services memory
bugzilla·2026-03-25·CVSS 5.5
CVE-2026-23352 [MEDIUM] CVE-2026-23352 kernel: x86/efi: defer freeing of boot services memory
CVE-2026-23352 kernel: x86/efi: defer freeing of boot services memory
In the Linux kernel, the following vulnerability has been resolved:
x86/efi: defer freeing of boot services memory
efi_free_boot_services() frees memory occupied by EFI_BOOT_SERVICES_CODE
and EFI_BOOT_SERVICES_DATA using memblock_free_late().
There are two issue with that: memblock_free_late() should be used for
memory allocated with memblock_alloc() while the memory reserved with
memblock_reserve() should be freed with free_reserved_area().
More acutely, with CONFIG_DEFERRED_STRUCT_PAGE_INIT=y
efi_free_boot_services() is called before deferred initialization of the
memory map is complete.
Benjamin Herrenschmidt reports that this causes a leak of ~140MB of
RAM on EC2 t3a.nano instances which only have 512MB or RAM.
https://git.kernel.org/stable/c/227688312fece0026fc67a00ba9a0b3611ebe95dhttps://git.kernel.org/stable/c/399da820ecfe6f4f10c143e5c453d3559a04db9chttps://git.kernel.org/stable/c/4a2cb90c538f06c873a187aa743575d48685d7a6https://git.kernel.org/stable/c/6a25e25279282c5c8ade554c04c6ab9dc7902c64https://git.kernel.org/stable/c/6d8ba221e7aafaa2f284b7d22faee814c28e009dhttps://git.kernel.org/stable/c/7131bd1fecc749bc94fb44aae217bbd8a8a85264https://git.kernel.org/stable/c/7dcf59422a3b0d20ddda844f856b4a1e0608a326https://git.kernel.org/stable/c/a4b0bf6a40f3c107c67a24fbc614510ef5719980https://git.kernel.org/stable/c/f9e9cc320854a76a39e7bc92d144554f3a727fad
2026-03-25
Published