CVE-2025-21693
published 2025-02-10CVE-2025-21693: In the Linux kernel, the following vulnerability has been resolved: mm: zswap: properly synchronize freeing resources during CPU hotunplug In zswap_compress()…
PriorityP338high7.8CVSS 3.1
AVLACLPRLUINSUCHIHAH
EPSS
0.20%
10.0th percentile
In the Linux kernel, the following vulnerability has been resolved:
mm: zswap: properly synchronize freeing resources during CPU hotunplug
In zswap_compress() and zswap_decompress(), the per-CPU acomp_ctx of the
current CPU at the beginning of the operation is retrieved and used
throughout. However, since neither preemption nor migration are disabled,
it is possible that the operation continues on a different CPU.
If the original CPU is hotunplugged while the acomp_ctx is still in use,
we run into a UAF bug as some of the resources attached to the acomp_ctx
are freed during hotunplug in zswap_cpu_comp_dead() (i.e.
acomp_ctx.buffer, acomp_ctx.req, or acomp_ctx.acomp).
The problem was introduced in commit 1ec3b5fe6eec ("mm/zswap: move to use
crypto_acomp API for hardware acceleration") when the switch to the
crypto_acomp API was made. Prior to that, the per-CPU crypto_comp was
retrieved using get_cpu_ptr() which disables preemption and makes sure the
CPU cannot go away from under us. Preemption cannot be disabled with the
crypto_acomp API as a sleepable context is needed.
Use the acomp_ctx.mutex to synchronize CPU hotplug callbacks allocating
and freeing resources with compression/decompression paths. Make sure
that acomp_ctx.req is NULL when the resources are freed. In the
compression/decompression paths, check if acomp_ctx.req is NULL after
acquiring the mutex (meaning the CPU was offlined) and retry on the new
CPU.
The initialization of acomp_ctx.mutex is moved from the CPU hotplug
callback to the pool initialization where it belongs (where the mutex is
allocated). In addition to adding clarity, this makes sure that CPU
hotplug cannot reinitialize a mutex that is already locked by
compression/decompression.
Previously a fix was attempted by holding cpus_read_lock() [1]. This
would have caused a potential deadlock as it is possible for code already
holding the lock to fall into reclaim and enter zswap (causing a
deadlock). A fix was also attempted using SRCU
Affected
21 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | linux | < linux 6.12.12-1 (forky) | linux 6.12.12-1 (forky) |
| linux | linux | — | — |
| linux | linux | >= 1ec3b5fe6eec782f4e5e0a80e4ce1909ffd5d161 < 8d29ff5d50304daa41dc3cfdda4a9d1e46cf5be1 | 8d29ff5d50304daa41dc3cfdda4a9d1e46cf5be1 |
| linux | linux | >= 1ec3b5fe6eec782f4e5e0a80e4ce1909ffd5d161 < 12dcb0ef540629a281533f9dedc1b6b8e14cfb65 | 12dcb0ef540629a281533f9dedc1b6b8e14cfb65 |
| linux | linux_kernel | — | — |
| linux | linux_kernel | >= 0 < 6.12.12-1 | 6.12.12-1 |
| linux | linux_kernel | >= 0 < 6.12.12-1 | 6.12.12-1 |
| linux | linux_kernel | >= 5.11 < 6.12.12 | 6.12.12 |
| msrc | azl3_kernel_6.6.104.2-4_on_azure_linux_3.0 | — | — |
| msrc | azl3_kernel_6.6.112.1-2_on_azure_linux_3.0 | — | — |
| msrc | azl3_kernel_6.6.117.1-1_on_azure_linux_3.0 | — | — |
| msrc | azl3_kernel_6.6.119.3-1_on_azure_linux_3.0 | — | — |
| msrc | azl3_kernel_6.6.119.3-3_on_azure_linux_3.0 | — | — |
| msrc | azl3_kernel_6.6.121.1-1_on_azure_linux_3.0 | — | — |
| msrc | azl3_kernel_6.6.126.1-1_on_azure_linux_3.0 | — | — |
| msrc | azl3_kernel_6.6.130.1-3_on_azure_linux_3.0 | — | — |
| msrc | azl3_kernel_6.6.96.2-1_on_azure_linux_3.0 | — | — |
| msrc | azl3_kernel_6.6.96.2-2_on_azure_linux_3.0 | — | — |
| msrc | cbl2_kernel_5.15.186.1-1_on_cbl_mariner_2.0 | — | — |
| msrc | cbl2_kernel_5.15.200.1-1_on_cbl_mariner_2.0 | — | — |
| msrc | cbl2_kernel_5.15.202.1-1_on_cbl_mariner_2.0 | — | — |
CVSS provenance
nvdv3.17.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
osv7.8HIGH
vendor_debian7.8HIGH
vendor_msrc7.8HIGH
vendor_redhat7.8HIGH
vendor_ubuntu5.5MEDIUM
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Ubuntu
Linux kernel vulnerabilities
vendor_ubuntu·2025-04-23·CVSS 5.5
CVE-2025-21695 [MEDIUM] Linux kernel vulnerabilities
Title: Linux kernel vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
It was discovered that the CIFS network file system implementation in the
Linux kernel did not properly verify the target namespace when handling
upcalls. An attacker could use this to expose sensitive information.
(CVE-2025-2312)
Several security issues were discovered in the Linux kernel.
An attacker could possibly use these to compromise the system.
This update corrects flaws in the following subsystems:
- GPIO subsystem;
- GPU drivers;
- IRQ chip drivers;
- Network drivers;
- Mellanox network drivers;
- x86 platform drivers;
- i.MX PM domains;
- SCSI subsystem;
- USB Serial drivers;
- AFS file system;
- GFS2 file system;
- File systems infrastructure;
- Proc file system;
- SMB networ
Ubuntu
Linux kernel vulnerabilities
vendor_ubuntu·2025-04-23·CVSS 5.5
CVE-2025-21695 [MEDIUM] Linux kernel vulnerabilities
Title: Linux kernel vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
Several security issues were discovered in the Linux kernel.
An attacker could possibly use these to compromise the system.
This update corrects flaws in the following subsystems:
- GPIO subsystem;
- GPU drivers;
- IRQ chip drivers;
- Network drivers;
- Mellanox network drivers;
- x86 platform drivers;
- i.MX PM domains;
- SCSI subsystem;
- USB Serial drivers;
- AFS file system;
- GFS2 file system;
- File systems infrastructure;
- Proc file system;
- SMB network file system;
- Timer subsystem;
- Kernel CPU control infrastructure;
- Memory management;
- Networking core;
- Ethtool driver;
- IEEE 802.15.4 subsystem;
- Open vSwitch;
- Network traffic control;
- VMware vSockets driver;
(CVE-20
Microsoft
mm: zswap: properly synchronize freeing resources during CPU hotunplug
vendor_msrc·2025-02-11·CVSS 7.8
CVE-2025-21693 [HIGH] CWE-416 mm: zswap: properly synchronize freeing resources during CPU hotunplug
mm: zswap: properly synchronize freeing resources during CPU hotunplug
FAQ: Is Azure Linux the only Microsoft product that includes this open-source library and is therefore potentially affected by this vulnerability?
One of the main benefits to our customers who choose to use the Azure Linux distro is the commitment to keep it up to date with the most recent and most secure versions of the open source libraries with which the distro is composed. Microsoft is committed to transparency in this work which is why we began publishing CSAF/VEX in October 2025. See this blog post for more information. If impact to additional products is identified, we will update the CVE to reflect this.
Mariner: Mariner
Linux: Linux
Customer Action Required: Yes
Red Hat
kernel: mm: zswap: properly synchronize freeing resources during CPU hotunplug
vendor_redhat·2025-02-10·CVSS 7.8
CVE-2025-21693 [HIGH] CWE-416 kernel: mm: zswap: properly synchronize freeing resources during CPU hotunplug
kernel: mm: zswap: properly synchronize freeing resources during CPU hotunplug
In the Linux kernel, the following vulnerability has been resolved:
mm: zswap: properly synchronize freeing resources during CPU hotunplug
In zswap_compress() and zswap_decompress(), the per-CPU acomp_ctx of the
current CPU at the beginning of the operation is retrieved and used
throughout. However, since neither preemption nor migration are disabled,
it is possible that the operation continues on a different CPU.
If the original CPU is hotunplugged while the acomp_ctx is still in use,
we run into a UAF bug as some of the resources attached to the acomp_ctx
are freed during hotunplug in zswap_cpu_comp_dead() (i.e.
acomp_ctx.buffer, acomp_ctx.req, or acomp_ctx.acomp).
The problem was introduced in commit 1ec3b5f
Debian
CVE-2025-21693: linux - In the Linux kernel, the following vulnerability has been resolved: mm: zswap: ...
vendor_debian·2025·CVSS 7.8
CVE-2025-21693 [HIGH] CVE-2025-21693: linux - In the Linux kernel, the following vulnerability has been resolved: mm: zswap: ...
In the Linux kernel, the following vulnerability has been resolved: mm: zswap: properly synchronize freeing resources during CPU hotunplug In zswap_compress() and zswap_decompress(), the per-CPU acomp_ctx of the current CPU at the beginning of the operation is retrieved and used throughout. However, since neither preemption nor migration are disabled, it is possible that the operation continues on a different CPU. If the original CPU is hotunplugged while the acomp_ctx is still in use, we run into a UAF bug as some of the resources attached to the acomp_ctx are freed during hotunplug in zswap_cpu_comp_dead() (i.e. acomp_ctx.buffer, acomp_ctx.req, or acomp_ctx.acomp). The problem was introduced in commit 1ec3b5fe6eec ("mm/zswap: move to use crypto_acomp API for hardware acceleration") when
OSV
linux, linux-aws, linux-gcp, linux-hwe-6.11, linux-lowlatency, linux-lowlatency-hwe-6.11, linux-oem-6.11, linux-oracle, linux-raspi, linux-realtime vulnerabilities
osv·2025-04-23·CVSS 5.5
[MEDIUM] linux, linux-aws, linux-gcp, linux-hwe-6.11, linux-lowlatency, linux-lowlatency-hwe-6.11, linux-oem-6.11, linux-oracle, linux-raspi, linux-realtime vulnerabilities
linux, linux-aws, linux-gcp, linux-hwe-6.11, linux-lowlatency, linux-lowlatency-hwe-6.11, linux-oem-6.11, linux-oracle, linux-raspi, linux-realtime vulnerabilities
Several security issues were discovered in the Linux kernel.
An attacker could possibly use these to compromise the system.
This update corrects flaws in the following subsystems:
- GPIO subsystem;
- GPU drivers;
- IRQ chip drivers;
- Network drivers;
- Mellanox network drivers;
- x86 platform drivers;
- i.MX PM domains;
- SCSI subsystem;
- USB Serial drivers;
- AFS file system;
- GFS2 file system;
- File systems infrastructure;
- Proc file system;
- SMB network file system;
- Timer subsystem;
- Kernel CPU control infrastructure;
- Memory management;
- Networking core;
- Ethtool driver;
- IEEE 802.15.4 subsystem;
- Open vSwitch
OSV
linux-azure, linux-azure-6.11 vulnerabilities
osv·2025-04-23·CVSS 5.5
CVE-2025-2312 [MEDIUM] linux-azure, linux-azure-6.11 vulnerabilities
linux-azure, linux-azure-6.11 vulnerabilities
It was discovered that the CIFS network file system implementation in the
Linux kernel did not properly verify the target namespace when handling
upcalls. An attacker could use this to expose sensitive information.
(CVE-2025-2312)
Several security issues were discovered in the Linux kernel.
An attacker could possibly use these to compromise the system.
This update corrects flaws in the following subsystems:
- GPIO subsystem;
- GPU drivers;
- IRQ chip drivers;
- Network drivers;
- Mellanox network drivers;
- x86 platform drivers;
- i.MX PM domains;
- SCSI subsystem;
- USB Serial drivers;
- AFS file system;
- GFS2 file system;
- File systems infrastructure;
- Proc file system;
- SMB network file system;
- Timer subsystem;
- Kernel CPU control i
GHSA
GHSA-jqr2-rwpf-xrf3: In the Linux kernel, the following vulnerability has been resolved:
mm: zswap: properly synchronize freeing resources during CPU hotunplug
In zswap_
ghsa_unreviewed·2025-02-10
CVE-2025-21693 [HIGH] CWE-416 GHSA-jqr2-rwpf-xrf3: In the Linux kernel, the following vulnerability has been resolved:
mm: zswap: properly synchronize freeing resources during CPU hotunplug
In zswap_
In the Linux kernel, the following vulnerability has been resolved:
mm: zswap: properly synchronize freeing resources during CPU hotunplug
In zswap_compress() and zswap_decompress(), the per-CPU acomp_ctx of the
current CPU at the beginning of the operation is retrieved and used
throughout. However, since neither preemption nor migration are disabled,
it is possible that the operation continues on a different CPU.
If the original CPU is hotunplugged while the acomp_ctx is still in use,
we run into a UAF bug as some of the resources attached to the acomp_ctx
are freed during hotunplug in zswap_cpu_comp_dead() (i.e.
acomp_ctx.buffer, acomp_ctx.req, or acomp_ctx.acomp).
The problem was introduced in commit 1ec3b5fe6eec ("mm/zswap: move to use
crypto_acomp API for hardware acceleration") w
OSV
CVE-2025-21693: In the Linux kernel, the following vulnerability has been resolved: mm: zswap: properly synchronize freeing resources during CPU hotunplug In zswap_co
osv·2025-02-10·CVSS 7.8
CVE-2025-21693 [HIGH] CVE-2025-21693: In the Linux kernel, the following vulnerability has been resolved: mm: zswap: properly synchronize freeing resources during CPU hotunplug In zswap_co
In the Linux kernel, the following vulnerability has been resolved: mm: zswap: properly synchronize freeing resources during CPU hotunplug In zswap_compress() and zswap_decompress(), the per-CPU acomp_ctx of the current CPU at the beginning of the operation is retrieved and used throughout. However, since neither preemption nor migration are disabled, it is possible that the operation continues on a different CPU. If the original CPU is hotunplugged while the acomp_ctx is still in use, we run into a UAF bug as some of the resources attached to the acomp_ctx are freed during hotunplug in zswap_cpu_comp_dead() (i.e. acomp_ctx.buffer, acomp_ctx.req, or acomp_ctx.acomp). The problem was introduced in commit 1ec3b5fe6eec ("mm/zswap: move to use crypto_acomp API for hardware acceleration") when
No detection rules found.
No public exploits indexed.
2025-02-10
Published