CVE-2026-23406
published 2026-04-01CVE-2026-23406: In the Linux kernel, the following vulnerability has been resolved: apparmor: fix side-effect bug in match_char() macro usage The match_char() macro evaluates…
PriorityP340high7.8CVSS 3.1
AVLACLPRLUINSUCHIHAH
EPSS
0.18%
7.4th percentile
In the Linux kernel, the following vulnerability has been resolved:
apparmor: fix side-effect bug in match_char() macro usage
The match_char() macro evaluates its character parameter multiple
times when traversing differential encoding chains. When invoked
with *str++, the string pointer advances on each iteration of the
inner do-while loop, causing the DFA to check different characters
at each iteration and therefore skip input characters.
This results in out-of-bounds reads when the pointer advances past
the input buffer boundary.
[ 94.984676] ==================================================================
[ 94.985301] BUG: KASAN: slab-out-of-bounds in aa_dfa_match+0x5ae/0x760
[ 94.985655] Read of size 1 at addr ffff888100342000 by task file/976
[ 94.986319] CPU: 7 UID: 1000 PID: 976 Comm: file Not tainted 6.19.0-rc7-next-20260127 #1 PREEMPT(lazy)
[ 94.986322] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[ 94.986329] Call Trace:
[ 94.986341]
[ 94.986347] dump_stack_lvl+0x5e/0x80
[ 94.986374] print_report+0xc8/0x270
[ 94.986384] ? aa_dfa_match+0x5ae/0x760
[ 94.986388] kasan_report+0x118/0x150
[ 94.986401] ? aa_dfa_match+0x5ae/0x760
[ 94.986405] aa_dfa_match+0x5ae/0x760
[ 94.986408] __aa_path_perm+0x131/0x400
[ 94.986418] aa_path_perm+0x219/0x2f0
[ 94.986424] apparmor_file_open+0x345/0x570
[ 94.986431] security_file_open+0x5c/0x140
[ 94.986442] do_dentry_open+0x2f6/0x1120
[ 94.986450] vfs_open+0x38/0x2b0
[ 94.986453] ? may_open+0x1e2/0x2b0
[ 94.986466] path_openat+0x231b/0x2b30
[ 94.986469] ? __x64_sys_openat+0xf8/0x130
[ 94.986477] do_file_open+0x19d/0x360
[ 94.986487] do_sys_openat2+0x98/0x100
[ 94.986491] __x64_sys_openat+0xf8/0x130
[ 94.986499] do_syscall_64+0x8e/0x660
[ 94.986515] ? count_memcg_events+0x15f/0x3c0
[ 94.986526] ? srso_alias_return_thunk+0x5/0xfbef5
[ 94.986540] ? handle_mm_fault+0x1639/0x1ef0
[ 94.986551] ? vma_start_read+0xf0/0x320
[ 94.986558] ? srso_alias_return_thunk+0x5/0xfbef5
[ 94.986561
Affected
29 ranges· showing 25
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | linux | < linux 6.1.164-1 (bookworm) | linux 6.1.164-1 (bookworm) |
| linux | linux | — | — |
| linux | linux | >= 074c1cd798cb0b481d7eaa749b64aa416563c053 < c7dc56d8b37eda1396feeec3ab1c7ecee5eae31b | c7dc56d8b37eda1396feeec3ab1c7ecee5eae31b |
| linux | linux | >= 074c1cd798cb0b481d7eaa749b64aa416563c053 < f16f2e5936c0f5f0d11fdf10d2be3e47e7108e42 | f16f2e5936c0f5f0d11fdf10d2be3e47e7108e42 |
| linux | linux | >= 074c1cd798cb0b481d7eaa749b64aa416563c053 < 1fc94f16098213d01e56c97feed9b3ecf0147a37 | 1fc94f16098213d01e56c97feed9b3ecf0147a37 |
| linux | linux | >= 074c1cd798cb0b481d7eaa749b64aa416563c053 < 5a184f7cbdeaad17e16dedf3c17d0cd622edfed8 | 5a184f7cbdeaad17e16dedf3c17d0cd622edfed8 |
| linux | linux | >= 074c1cd798cb0b481d7eaa749b64aa416563c053 < b73c1dff8a9d7eeaebabf8097a5b2de192f40913 | b73c1dff8a9d7eeaebabf8097a5b2de192f40913 |
| linux | linux | >= 074c1cd798cb0b481d7eaa749b64aa416563c053 < 0510d1ba0976f97f521feb2b75b0572ea5df3ceb | 0510d1ba0976f97f521feb2b75b0572ea5df3ceb |
| linux | linux | >= 074c1cd798cb0b481d7eaa749b64aa416563c053 < 383b7270faf42564f133134c2fc3c24bbae52615 | 383b7270faf42564f133134c2fc3c24bbae52615 |
| linux | linux | >= 074c1cd798cb0b481d7eaa749b64aa416563c053 < 8756b68edae37ff546c02091989a4ceab3f20abd | 8756b68edae37ff546c02091989a4ceab3f20abd |
| linux | linux_kernel | — | — |
| linux | linux_kernel | — | — |
| linux | linux_kernel | >= 0 < 5.10.251-1 | 5.10.251-1 |
| linux | linux_kernel | >= 0 < 6.1.164-1 | 6.1.164-1 |
| linux | linux_kernel | >= 0 < 6.12.74-2 | 6.12.74-2 |
| linux | linux_kernel | >= 0 < 6.19.6-2 | 6.19.6-2 |
| linux | linux_kernel | >= 4.17.1 < 5.10.253 | 5.10.253 |
| linux | linux_kernel | >= 5.11 < 5.15.203 | 5.15.203 |
| linux | linux_kernel | >= 5.16 < 6.1.169 | 6.1.169 |
| linux | linux_kernel | >= 6.13 < 6.18.18 | 6.18.18 |
| linux | linux_kernel | >= 6.19 < 6.19.8 | 6.19.8 |
| linux | linux_kernel | >= 6.2 < 6.6.130 | 6.6.130 |
| linux | linux_kernel | >= 6.7 < 6.12.77 | 6.12.77 |
| ubuntu | linux-azure-5.15 | — | — |
| ubuntu | linux-azure-5.4 | — | — |
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_redhat7.8HIGH
vendor_ubuntu7.8HIGH
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Ubuntu
Linux kernel (Xilinx) vulnerabilities
vendor_ubuntu·2026-05-07·CVSS 6.4
CVE-2025-68288 [MEDIUM] Linux kernel (Xilinx) vulnerabilities
Title: Linux kernel (Xilinx) vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
Josh Eads, Kristoffer Janke, Eduardo Vela Nava, Tavis Ormandy, and Matteo
Rizzo discovered that some AMD Zen processors did not properly verify the
signature of CPU microcode. This flaw is known as EntrySign. A privileged
attacker could possibly use this issue to cause load malicious CPU
microcode causing loss of integrity and confidentiality. (CVE-2024-36347)
Qualys discovered that several vulnerabilities existed in the AppArmor
Linux kernel Security Module (LSM). An unprivileged local attacker could
use these issues to load, replace, and remove arbitrary AppArmor profiles
causing denial of service, exposure of sensitive information (kernel
memory), local privilege escalation,
Ubuntu
Linux kernel (Azure) vulnerabilities
vendor_ubuntu·2026-05-07·CVSS 7.8
CVE-2025-22058 [HIGH] Linux kernel (Azure) vulnerabilities
Title: Linux kernel (Azure) vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
Qualys discovered that several vulnerabilities existed in the AppArmor
Linux kernel Security Module (LSM). An unprivileged local attacker could
use these issues to load, replace, and remove arbitrary AppArmor profiles
causing denial of service, exposure of sensitive information (kernel
memory), local privilege escalation, or possibly escape a container.
(LP: #2143853, CVE-2026-23268, CVE-2026-23269, CVE-2026-23403,
CVE-2026-23404, CVE-2026-23405, CVE-2026-23406, CVE-2026-23407,
CVE-2026-23408, CVE-2026-23409, CVE-2026-23410, CVE-2026-23411)
Several security issues were discovered in the Linux kernel.
An attacker could possibly use these to compromise the system.
This update corre
Ubuntu
Linux kernel (BlueField) vulnerabilities
vendor_ubuntu·2026-04-29·CVSS 4.7
CVE-2022-48875 [MEDIUM] Linux kernel (BlueField) vulnerabilities
Title: Linux kernel (BlueField) vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
Qualys discovered that several vulnerabilities existed in the AppArmor
Linux kernel Security Module (LSM). An unprivileged local attacker could
use these issues to load, replace, and remove arbitrary AppArmor profiles
causing denial of service, exposure of sensitive information (kernel
memory), local privilege escalation, or possibly escape a container.
(LP: #2143853, CVE-2026-23268, CVE-2026-23269, CVE-2026-23403,
CVE-2026-23404, CVE-2026-23405, CVE-2026-23406, CVE-2026-23407,
CVE-2026-23408, CVE-2026-23409, CVE-2026-23410, CVE-2026-23411)
Several security issues were discovered in the Linux kernel.
An attacker could possibly use these to compromise the system.
This update c
Ubuntu
Linux kernel (Azure) vulnerabilities
vendor_ubuntu·2026-04-22·CVSS 4.7
CVE-2026-23410 [MEDIUM] Linux kernel (Azure) vulnerabilities
Title: Linux kernel (Azure) vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
Qualys discovered that several vulnerabilities existed in the AppArmor
Linux kernel Security Module (LSM). An unprivileged local attacker could
use these issues to load, replace, and remove arbitrary AppArmor profiles
causing denial of service, exposure of sensitive information (kernel
memory), local privilege escalation, or possibly escape a container.
(LP: #2143853, CVE-2026-23268, CVE-2026-23269, CVE-2026-23403,
CVE-2026-23404, CVE-2026-23405, CVE-2026-23406, CVE-2026-23407,
CVE-2026-23408, CVE-2026-23409, CVE-2026-23410, CVE-2026-23411)
Several security issues were discovered in the Linux kernel.
An attacker could possibly use these to compromise the system.
This update corre
Ubuntu
Linux kernel (Raspberry Pi) vulnerabilities
vendor_ubuntu·2026-04-20·CVSS 4.7
CVE-2025-40215 [MEDIUM] Linux kernel (Raspberry Pi) vulnerabilities
Title: Linux kernel (Raspberry Pi) vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
Qualys discovered that several vulnerabilities existed in the AppArmor
Linux kernel Security Module (LSM). An unprivileged local attacker could
use these issues to load, replace, and remove arbitrary AppArmor profiles
causing denial of service, exposure of sensitive information (kernel
memory), local privilege escalation, or possibly escape a container.
(LP: #2143853)
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:
- x86 architecture;
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- GPU drivers;
- BTRFS file system;
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- IPv4 networking;
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Ubuntu
Linux kernel (Azure) vulnerabilities
vendor_ubuntu·2026-04-13·CVSS 7.8
CVE-2024-53114 [HIGH] Linux kernel (Azure) vulnerabilities
Title: Linux kernel (Azure) vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
Qualys discovered that several vulnerabilities existed in the AppArmor
Linux kernel Security Module (LSM). An unprivileged local attacker could
use these issues to load, replace, and remove arbitrary AppArmor profiles
causing denial of service, exposure of sensitive information (kernel
memory), local privilege escalation, or possibly escape a container.
(LP: #2143853, CVE-2026-23268, CVE-2026-23269, CVE-2026-23403,
CVE-2026-23404, CVE-2026-23405, CVE-2026-23406, CVE-2026-23407,
CVE-2026-23408, CVE-2026-23409, CVE-2026-23410, CVE-2026-23411)
Several security issues were discovered in the Linux kernel.
An attacker could possibly use these to compromise the system.
This update corre
Ubuntu
Linux kernel (Azure FIPS) vulnerabilities
vendor_ubuntu·2026-04-09·CVSS 7.8
CVE-2025-21833 [HIGH] Linux kernel (Azure FIPS) vulnerabilities
Title: Linux kernel (Azure FIPS) vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
Qualys discovered that several vulnerabilities existed in the AppArmor
Linux kernel Security Module (LSM). An unprivileged local attacker could
use these issues to load, replace, and remove arbitrary AppArmor profiles
causing denial of service, exposure of sensitive information (kernel
memory), local privilege escalation, or possibly escape a container.
(LP: #2143853, CVE-2026-23268, CVE-2026-23269, CVE-2026-23403,
CVE-2026-23404, CVE-2026-23405, CVE-2026-23406, CVE-2026-23407,
CVE-2026-23408, CVE-2026-23409, CVE-2026-23410, CVE-2026-23411)
Several security issues were discovered in the Linux kernel.
An attacker could possibly use these to compromise the system.
This update
Ubuntu
Linux kernel (Azure FIPS) vulnerabilities
vendor_ubuntu·2026-04-09·CVSS 7.8
CVE-2025-71125 [HIGH] Linux kernel (Azure FIPS) vulnerabilities
Title: Linux kernel (Azure FIPS) vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
Qualys discovered that several vulnerabilities existed in the AppArmor
Linux kernel Security Module (LSM). An unprivileged local attacker could
use these issues to load, replace, and remove arbitrary AppArmor profiles
causing denial of service, exposure of sensitive information (kernel
memory), local privilege escalation, or possibly escape a container.
(LP: #2143853, CVE-2026-23268, CVE-2026-23269, CVE-2026-23403,
CVE-2026-23404, CVE-2026-23405, CVE-2026-23406, CVE-2026-23407,
CVE-2026-23408, CVE-2026-23409, CVE-2026-23410, CVE-2026-23411)
Several security issues were discovered in the Linux kernel.
An attacker could possibly use these to compromise the system.
This update
Ubuntu
Linux kernel (Intel IoTG Real-time) vulnerabilities
vendor_ubuntu·2026-04-09·CVSS 7.8
CVE-2026-23410 [HIGH] Linux kernel (Intel IoTG Real-time) vulnerabilities
Title: Linux kernel (Intel IoTG Real-time) vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
Qualys discovered that several vulnerabilities existed in the AppArmor
Linux kernel Security Module (LSM). An unprivileged local attacker could
use these issues to load, replace, and remove arbitrary AppArmor profiles
causing denial of service, exposure of sensitive information (kernel
memory), local privilege escalation, or possibly escape a container.
(LP: #2143853, CVE-2026-23268, CVE-2026-23269, CVE-2026-23403,
CVE-2026-23404, CVE-2026-23405, CVE-2026-23406, CVE-2026-23407,
CVE-2026-23408, CVE-2026-23409, CVE-2026-23410, CVE-2026-23411)
Several security issues were discovered in the Linux kernel.
An attacker could possibly use these to compromise the system.
Th
Ubuntu
Linux kernel (OEM) vulnerabilities
vendor_ubuntu·2026-04-06·CVSS 7.2
CVE-2026-23404 [HIGH] Linux kernel (OEM) vulnerabilities
Title: Linux kernel (OEM) vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
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 attacker could
possibly use this issue to influence the values returned by the RDSEED
instruction causing loss of confidentiality and integrity. (CVE-2025-62626)
Qualys discovered that several vulnerabilities existed in the AppArmor
Linux kernel Security Module (LSM). An unprivileged local attacker could
use these issues to load, replace, and remove arbitrary AppArmor profiles
causing denial of service, exposure of sensitive information (kernel
memory), local privilege escalation, or possibl
Red Hat
kernel: apparmor: fix side-effect bug in match_char() macro usage
vendor_redhat·2026-04-01·CVSS 7.8
CVE-2026-23406 [HIGH] CWE-788 kernel: apparmor: fix side-effect bug in match_char() macro usage
kernel: apparmor: fix side-effect bug in match_char() macro usage
In the Linux kernel, the following vulnerability has been resolved:
apparmor: fix side-effect bug in match_char() macro usage
The match_char() macro evaluates its character parameter multiple
times when traversing differential encoding chains. When invoked
with *str++, the string pointer advances on each iteration of the
inner do-while loop, causing the DFA to check different characters
at each iteration and therefore skip input characters.
This results in out-of-bounds reads when the pointer advances past
the input buffer boundary.
[ 94.984676] ==================================================================
[ 94.985301] BUG: KASAN: slab-out-of-bounds in aa_dfa_match+0x5ae/0x760
[ 94.985655] Read of size 1 at addr ffff88
Debian
CVE-2026-23406: linux - In the Linux kernel, the following vulnerability has been resolved: apparmor: f...
vendor_debian·2026·CVSS 7.8
CVE-2026-23406 [HIGH] CVE-2026-23406: linux - In the Linux kernel, the following vulnerability has been resolved: apparmor: f...
In the Linux kernel, the following vulnerability has been resolved: apparmor: fix side-effect bug in match_char() macro usage The match_char() macro evaluates its character parameter multiple times when traversing differential encoding chains. When invoked with *str++, the string pointer advances on each iteration of the inner do-while loop, causing the DFA to check different characters at each iteration and therefore skip input characters. This results in out-of-bounds reads when the pointer advances past the input buffer boundary. [ 94.984676] ================================================================== [ 94.985301] BUG: KASAN: slab-out-of-bounds in aa_dfa_match+0x5ae/0x760 [ 94.985655] Read of size 1 at addr ffff888100342000 by task file/976 [ 94.986319] CPU: 7 UID: 1000 PID: 976
VulDB
Linux Kernel up to 7.0-rc3 apparmor match_char out-of-bounds (EUVD-2026-17834 / WID-SEC-2026-0950)
vuldb·2026-04-19·CVSS 7.8
CVE-2026-23406 [HIGH] Linux Kernel up to 7.0-rc3 apparmor match_char out-of-bounds (EUVD-2026-17834 / WID-SEC-2026-0950)
A vulnerability labeled as critical has been found in Linux Kernel up to 6.6.129/6.12.76/6.18.17/6.19.7/7.0-rc3. This impacts the function match_char of the component apparmor. Executing a manipulation can lead to out-of-bounds read.
This vulnerability is handled as CVE-2026-23406. The attack can only be done within the local network. There is not any exploit available.
The affected component should be upgraded.
OSV
linux-oem-6.17 vulnerabilities
osv·2026-04-06·CVSS 7.2
CVE-2025-62626 [HIGH] linux-oem-6.17 vulnerabilities
linux-oem-6.17 vulnerabilities
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 attacker could
possibly use this issue to influence the values returned by the RDSEED
instruction causing loss of confidentiality and integrity. (CVE-2025-62626)
Qualys discovered that several vulnerabilities existed in the AppArmor
Linux kernel Security Module (LSM). An unprivileged local attacker could
use these issues to load, replace, and remove arbitrary AppArmor profiles
causing denial of service, exposure of sensitive information (kernel
memory), local privilege escalation, or possibly escape a container.
(LP: #2143853, CVE-2026-23268, CVE-2026-23269, CVE-2026
GHSA
GHSA-56hx-r887-5w6h: In the Linux kernel, the following vulnerability has been resolved:
apparmor: fix side-effect bug in match_char() macro usage
The match_char() macro
ghsa_unreviewed·2026-04-01
CVE-2026-23406 [HIGH] GHSA-56hx-r887-5w6h: In the Linux kernel, the following vulnerability has been resolved:
apparmor: fix side-effect bug in match_char() macro usage
The match_char() macro
In the Linux kernel, the following vulnerability has been resolved:
apparmor: fix side-effect bug in match_char() macro usage
The match_char() macro evaluates its character parameter multiple
times when traversing differential encoding chains. When invoked
with *str++, the string pointer advances on each iteration of the
inner do-while loop, causing the DFA to check different characters
at each iteration and therefore skip input characters.
This results in out-of-bounds reads when the pointer advances past
the input buffer boundary.
[ 94.984676] ==================================================================
[ 94.985301] BUG: KASAN: slab-out-of-bounds in aa_dfa_match+0x5ae/0x760
[ 94.985655] Read of size 1 at addr ffff888100342000 by task file/976
[ 94.986319] CPU: 7 UID: 1000 PID:
OSV
CVE-2026-23406: In the Linux kernel, the following vulnerability has been resolved: apparmor: fix side-effect bug in match_char() macro usage The match_char() macro e
osv·2026-04-01·CVSS 7.8
CVE-2026-23406 [HIGH] CVE-2026-23406: In the Linux kernel, the following vulnerability has been resolved: apparmor: fix side-effect bug in match_char() macro usage The match_char() macro e
In the Linux kernel, the following vulnerability has been resolved: apparmor: fix side-effect bug in match_char() macro usage The match_char() macro evaluates its character parameter multiple times when traversing differential encoding chains. When invoked with *str++, the string pointer advances on each iteration of the inner do-while loop, causing the DFA to check different characters at each iteration and therefore skip input characters. This results in out-of-bounds reads when the pointer advances past the input buffer boundary. [ 94.984676] ================================================================== [ 94.985301] BUG: KASAN: slab-out-of-bounds in aa_dfa_match+0x5ae/0x760 [ 94.985655] Read of size 1 at addr ffff888100342000 by task file/976 [ 94.986319] CPU: 7 UID: 1000 PID: 976
No detection rules found.
No public exploits indexed.
https://git.kernel.org/stable/c/0510d1ba0976f97f521feb2b75b0572ea5df3cebhttps://git.kernel.org/stable/c/1fc94f16098213d01e56c97feed9b3ecf0147a37https://git.kernel.org/stable/c/383b7270faf42564f133134c2fc3c24bbae52615https://git.kernel.org/stable/c/5a184f7cbdeaad17e16dedf3c17d0cd622edfed8https://git.kernel.org/stable/c/8756b68edae37ff546c02091989a4ceab3f20abdhttps://git.kernel.org/stable/c/b73c1dff8a9d7eeaebabf8097a5b2de192f40913https://git.kernel.org/stable/c/c7dc56d8b37eda1396feeec3ab1c7ecee5eae31bhttps://git.kernel.org/stable/c/f16f2e5936c0f5f0d11fdf10d2be3e47e7108e42
2026-04-01
Published