Description
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] <TASK>
[ 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] ? srso_alias_return_thunk+0x5/0xfbef5
[ 94.986563] ? fpregs_assert_state_consistent+0x50/0xe0
[ 94.986572] ? srso_alias_return_thunk+0x5/0xfbef5
[ 94.986574] ? arch_exit_to_user_mode_prepare+0x9/0xb0
[ 94.986587] ? srso_alias_return_thunk+0x5/0xfbef5
[ 94.986588] ? irqentry_exit+0x3c/0x590
[ 94.986595] entry_SYSCALL_64_after_hwframe+0x76/0x7e
[ 94.986597] RIP: 0033:0x7fda4a79c3ea
Fix by extracting the character value before invoking match_char,
ensuring single evaluation per outer loop.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Linux | Linux | 4.17 | 5.10.253 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | linux | 6.19.6-2 | — |
| Debian 13 | linux | 6.12.74-2 | — |
| Debian 12 | linux | 6.1.164-1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Nvidia-BlueField 24.04 LTS | linux-bluefield | 6.8.0-1017.21 | — |
| Ubuntu Nvidia-BlueField 22.04 LTS | linux-bluefield | 5.15.0-1087.89 | — |
| Ubuntu 25.10 | linux | 6.17.0-19.19 | — |
| Ubuntu 25.10 | linux-aws +2 | 6.17.0-1009.9 | — |
| Ubuntu 25.10 | linux-azure +1 | 6.17.0-1010.10 | — |
| Ubuntu 25.10 | linux-azure-fde | No fix yet | — |
| Ubuntu 25.10 | linux-realtime | 6.17.0-1008.9 | — |
| Ubuntu 25.10 | linux-riscv | 6.17.0-19.19.1 | — |
| Ubuntu 24.04 LTS | linux | 6.8.0-106.106 | — |
| Ubuntu 24.04 LTS | linux-aws | 6.8.0-1050.53 | — |
| Ubuntu 24.04 LTS | linux-aws-6.17 | 6.17.0-1009.9~24.04.2 | — |
| Ubuntu 24.04 LTS | linux-azure | 6.8.0-1051.57 | — |
| Ubuntu 24.04 LTS | linux-azure-6.17 | 6.17.0-1010.10~24.04.1 | — |
| Ubuntu 24.04 LTS | linux-azure-fde | 6.8.0-1058.65 | — |
| Ubuntu 24.04 LTS | linux-azure-nvidia | 6.8.0-1039.42 | — |
| Ubuntu 24.04 LTS | linux-gcp | 6.8.0-1052.55 | — |
| Ubuntu 24.04 LTS | linux-gcp-6.17 | 6.17.0-1009.9~24.04.3 | — |
| Ubuntu 24.04 LTS | linux-gke | 6.8.0-1048.53 | — |
| Ubuntu 24.04 LTS | linux-gkeop | 6.8.0-1035.38 | — |
| Ubuntu 24.04 LTS | linux-hwe-6.17 | 6.17.0-19.19~24.04.2 | — |
| Ubuntu 24.04 LTS | linux-ibm | 6.8.0-1049.49 | — |
| Ubuntu 24.04 LTS | linux-lowlatency | 6.8.0-106.106.1 | — |
| Ubuntu 24.04 LTS | linux-nvidia | 6.8.0-1049.52 | — |
| Ubuntu 24.04 LTS | linux-nvidia-6.17 | 6.17.0-1014.14 | — |
| Ubuntu 24.04 LTS | linux-nvidia-lowlatency | 6.8.0-1049.52.1 | — |
| Ubuntu 24.04 LTS | linux-nvidia-tegra | 6.8.0-1020.20 | — |
| Ubuntu 24.04 LTS | linux-oem-6.17 | 6.17.0-1017.17 | USN-8152-1 |
| Ubuntu 24.04 LTS | linux-oracle | 6.8.0-1047.48 | — |
| Ubuntu 24.04 LTS | linux-oracle-6.17 | 6.17.0-1009.9~24.04.1 | — |
| Ubuntu 24.04 LTS | linux-raspi | 6.8.0-1050.54 | — |
| Ubuntu 24.04 LTS | linux-riscv +18 | No fix yet | — |
| Ubuntu 24.04 LTS | linux-riscv-6.17 | 6.17.0-19.19.1~24.04.1 | — |
| Ubuntu 24.04 LTS | linux-xilinx | 6.8.0-1028.29 | USN-8261-1 |
| Ubuntu 22.04 LTS | linux +1 | 5.15.0-173.183 | — |
| Ubuntu 22.04 LTS | linux-aws | 5.15.0-1103.110 | — |
| Ubuntu 22.04 LTS | linux-aws-6.8 | 6.8.0-1050.53~22.04.1 | — |
| Ubuntu 22.04 LTS | linux-azure | 5.15.0-1109.118 | USN-8163-2 |
| Ubuntu 22.04 LTS | linux-azure-6.8 | 6.8.0-1051.57~22.04.1 | — |
| Ubuntu 22.04 LTS | linux-azure-fde | 5.15.0-1109.118.1 | — |
| Ubuntu 22.04 LTS | linux-azure-fde-6.8 | 6.8.0-1058.65~22.04.1 | — |
| Ubuntu 22.04 LTS | linux-gcp | 5.15.0-1103.112 | — |
| Ubuntu 22.04 LTS | linux-gcp-6.8 | 6.8.0-1052.55~22.04.1 | — |
| Ubuntu 22.04 LTS | linux-gke | 5.15.0-1099.105 | — |
| Ubuntu 22.04 LTS | linux-gkeop | 5.15.0-1086.94 | — |
| Ubuntu 22.04 LTS | linux-hwe-6.8 +1 | 6.8.0-106.106~22.04.1 | — |
| Ubuntu 22.04 LTS | linux-ibm +1 | 5.15.0-1097.100 | — |
| Ubuntu 22.04 LTS | linux-ibm-6.8 | 6.8.0-1049.49~22.04.1 | — |
| Ubuntu 22.04 LTS | linux-intel-iotg | 5.15.0-1098.104 | — |
| Ubuntu 22.04 LTS | linux-kvm | 5.15.0-1095.100 | — |
| Ubuntu 22.04 LTS | linux-lowlatency-hwe-6.8 | 6.8.0-106.106.1~22.04.1 | — |
| Ubuntu 22.04 LTS | linux-nvidia | 5.15.0-1098.99 | — |
| Ubuntu 22.04 LTS | linux-nvidia-6.8 | 6.8.0-1049.52~22.04.1 | — |
| Ubuntu 22.04 LTS | linux-nvidia-tegra | 5.15.0-1055.55 | — |
| Ubuntu 22.04 LTS | linux-nvidia-tegra-igx | 5.15.0-1044.44 | — |
| Ubuntu 22.04 LTS | linux-oracle | 5.15.0-1100.106 | — |
| Ubuntu 22.04 LTS | linux-oracle-6.8 | 6.8.0-1047.48~22.04.1 | — |
| Ubuntu 22.04 LTS | linux-riscv +32 | No fix yet | — |
| Ubuntu 22.04 LTS | linux-xilinx-zynqmp | 5.15.0-1067.71 | — |
Show 12 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | linux-gke +28 | No fix yet | — |
| Ubuntu 18.04 LTS | linux-gcp +14 | No fix yet | — |
| Ubuntu 16.04 LTS | linux-hwe-edge | No fix yet | — |
| Ubuntu Pro Realtime 24.04 LTS | linux-raspi-realtime | 6.8.0-2040.41 | — |
| Ubuntu Pro Realtime 24.04 LTS | linux-realtime | 6.8.1-1045.46 | — |
| Ubuntu Pro Realtime 24.04 LTS | linux-realtime-6.14 | No fix yet | — |
| Ubuntu Pro Realtime 24.04 LTS | linux-realtime-6.17 | 6.17.0-1008.9~24.04.1 | — |
| Ubuntu Pro Realtime 22.04 LTS | linux-intel-iot-realtime | 5.15.0-1096.98 | USN-8164-1 |
| Ubuntu Pro Realtime 22.04 LTS | linux-realtime | 5.15.0-1102.111 | — |
| Ubuntu Pro Realtime 22.04 LTS | linux-realtime-6.8 | 6.8.1-1045.46~22.04.1 | — |
| Ubuntu Pro FIPS 20.04 LTS | linux-fips +3 | No fix yet | — |
| Ubuntu Pro FIPS-updates 24.04 LTS | linux-aws-fips | 6.8.0-1050.53+fips1 | — |
| Ubuntu Pro FIPS-updates 24.04 LTS | linux-azure-fips | 6.8.0-1052.58+fips1 | USN-8165-1 |
| Ubuntu Pro FIPS-updates 24.04 LTS | linux-fips | 6.8.0-106.106+fips1 | — |
| Ubuntu Pro FIPS-updates 24.04 LTS | linux-gcp-fips | 6.8.0-1052.55+fips1 | — |
| Ubuntu Pro FIPS-updates 22.04 LTS | linux-aws-fips | 5.15.0-1103.110+fips1 | — |
| Ubuntu Pro FIPS-updates 22.04 LTS | linux-azure-fips | 5.15.0-1109.118+fips1 | USN-8163-1 |
| Ubuntu Pro FIPS-updates 22.04 LTS | linux-fips | 5.15.0-173.183+fips1 | — |
| Ubuntu Pro FIPS-updates 22.04 LTS | linux-gcp-fips | 5.15.0-1103.112+fips1 | — |
| Ubuntu Pro FIPS-updates 20.04 LTS | linux-aws-fips | 5.4.0-1156.166+fips1 | — |
| Ubuntu Pro FIPS-updates 20.04 LTS | linux-azure-fips | 5.4.0-1160.166+fips1 | — |
| Ubuntu Pro FIPS-updates 20.04 LTS | linux-fips | 5.4.0-1130.140 | — |
| Ubuntu Pro FIPS-updates 20.04 LTS | linux-gcp-fips | 5.4.0-1159.168+fips1 | — |
| Ubuntu Pro FIPS-preview 22.04 LTS | linux-fips +3 | No fix yet | — |
| Ubuntu Pro 20.04 LTS | linux | 5.4.0-227.247 | — |
| Ubuntu Pro 20.04 LTS | linux-aws | 5.4.0-1156.166 | — |
| Ubuntu Pro 20.04 LTS | linux-aws-5.15 | 5.15.0-1103.110~20.04.1 | — |
| Ubuntu Pro 20.04 LTS | linux-azure | 5.4.0-1160.166 | — |
| Ubuntu Pro 20.04 LTS | linux-azure-5.15 | 5.15.0-1110.119~20.04.1 | USN-8243-1 |
| Ubuntu Pro 20.04 LTS | linux-bluefield | 5.4.0-1116.123 | USN-8224-1 |
| Ubuntu Pro 20.04 LTS | linux-gcp | 5.4.0-1159.168 | — |
| Ubuntu Pro 20.04 LTS | linux-gcp-5.15 | 5.15.0-1103.112~20.04.1 | — |
| Ubuntu Pro 20.04 LTS | linux-hwe-5.15 +1 | 5.15.0-173.183~20.04.1 | — |
| Ubuntu Pro 20.04 LTS | linux-ibm | 5.4.0-1102.107 | — |
| Ubuntu Pro 20.04 LTS | linux-ibm-5.15 | 5.15.0-1097.100~20.04.1 | — |
| Ubuntu Pro 20.04 LTS | linux-intel-iotg-5.15 | 5.15.0-1098.104~20.04.1 | — |
| Ubuntu Pro 20.04 LTS | linux-iot | 5.4.0-1060.63 | — |
| Ubuntu Pro 20.04 LTS | linux-kvm | 5.4.0-1143.152 | — |
| Ubuntu Pro 20.04 LTS | linux-nvidia-tegra-5.15 | 5.15.0-1055.55~20.04.1 | — |
| Ubuntu Pro 20.04 LTS | linux-oracle | 5.4.0-1154.164 | — |
| Ubuntu Pro 20.04 LTS | linux-oracle-5.15 | 5.15.0-1100.106~20.04.1 | — |
| Ubuntu Pro 20.04 LTS | linux-raspi | 5.4.0-1139.152 | USN-8098-10 |
| Ubuntu Pro 20.04 LTS | linux-riscv-5.15 | 5.15.0-1098.102~20.04.1 | — |
| Ubuntu Pro 20.04 LTS | linux-xilinx-zynqmp | 5.4.0-1074.78 | — |
| Ubuntu Pro 18.04 LTS | linux-aws-5.4 | 5.4.0-1156.166~18.04.1 | — |
| Ubuntu Pro 18.04 LTS | linux-azure-5.4 | 5.4.0-1161.167~18.04.1 | USN-8201-1 |
| Ubuntu Pro 18.04 LTS | linux-gcp-5.4 | 5.4.0-1159.168~18.04.1 | — |
| Ubuntu Pro 18.04 LTS | linux-hwe-5.4 | 5.4.0-227.247~18.04.1 | — |
| Ubuntu Pro 18.04 LTS | linux-ibm-5.4 | 5.4.0-1102.107~18.04.1 | — |
| Ubuntu Pro 18.04 LTS | linux-oracle-5.4 | 5.4.0-1154.164~18.04.1 | — |
| Ubuntu Pro 18.04 LTS | linux-raspi-5.4 | 5.4.0-1139.152~18.04.1 | USN-8098-10 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | kernel-64kb +7 | 6.4.0-150700.53.55.1 | SUSE-SU-2026:2238-1 |
| SLES 15 SP7 | kernel-default-base | 6.4.0-150700.53.55.1.150700.17.33.1 | SUSE-SU-2026:2238-1 |
| SLES 15 SP6 | kernel-64kb +6 | 6.4.0-150600.23.112.1 | SUSE-SU-2026:2195-1 |
| SLES 15 SP6 | kernel-default-base | 6.4.0-150600.23.112.1.150600.12.52.1 | SUSE-SU-2026:2195-1 |
Show 4 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 15 SP6 | kernel-default-base | 6.4.0-150600.23.112.1.150600.12.52.1 | SUSE-SU-2026:2195-1 |
| SLES for SAP 15 SP6 | kernel-docs +4 | 6.4.0-150600.23.112.1 | SUSE-SU-2026:2195-1 |
| SLE Micro 6.2 | kernel-syms +1 | 6.12.0-160000.33.1 | SUSE-SU-2026:21834-1 |
| SLE Live Patching 15 SP7 | kernel-default | 6.4.0-150700.53.55.1 | SUSE-SU-2026:2238-1 |
| SLE Live Patching 15 SP7 | kernel-livepatch-SLE15-SP7_Update_15 | 1-150700.15.3.1 | SUSE-SU-2026:2238-1 |
| SLE Live Patching 15 SP6 | kernel-default | 6.4.0-150600.23.112.1 | SUSE-SU-2026:2195-1 |
| SLE Live Patching 15 SP6 | kernel-livepatch-SLE15-SP6_Update_26 | 1-150600.13.3.1 | SUSE-SU-2026:2195-1 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | kernel | 6.6.130.1-1 | — |
Advisories 14
- USN-8243-1 linux-azure-5.15 vulnerabilities Ubuntu Security Notices (USN) · Nov 4, 2026
- USN-8224-1 linux-bluefield vulnerabilities Ubuntu Security Notices (USN) · Nov 4, 2026
- USN-8201-1 linux-azure-5.4 vulnerabilities Ubuntu Security Notices (USN) · Nov 4, 2026
- USN-8152-1 linux-oem-6.17 vulnerabilities Ubuntu Security Notices (USN) · Nov 4, 2026
- USN-8163-1 linux-azure-fips vulnerabilities Ubuntu Security Notices (USN) · Nov 4, 2026
- USN-8164-1 linux-intel-iot-realtime vulnerabilities Ubuntu Security Notices (USN) · Nov 4, 2026
- USN-8165-1 linux-azure-fips vulnerabilities Ubuntu Security Notices (USN) · Nov 4, 2026
- USN-8163-2 linux-azure vulnerabilities Ubuntu Security Notices (USN) · Nov 4, 2026
- USN-8098-10 linux-raspi, linux-raspi-5.4 vulnerabilities Ubuntu Security Notices (USN) · Nov 4, 2026
- WID-SEC-2026-0950 Linux Kernel: Mehrere Schwachstellen BSI CERT-Bund (WID) · Oct 4, 2026
- USN-8261-1 linux-xilinx vulnerabilities Ubuntu Security Notices (USN) · Sep 7, 2026
- SUSE-SU-2026:21834-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Jul 9, 2026
- SUSE-SU-2026:2238-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Jul 1, 2026
- SUSE-SU-2026:2195-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Jul 1, 2026
References
- https://git.kernel.org/stable/c/c7dc56d8b37eda1396feeec3ab1c7ecee5eae31b
- https://git.kernel.org/stable/c/f16f2e5936c0f5f0d11fdf10d2be3e47e7108e42
- https://git.kernel.org/stable/c/1fc94f16098213d01e56c97feed9b3ecf0147a37
- https://git.kernel.org/stable/c/5a184f7cbdeaad17e16dedf3c17d0cd622edfed8
- https://git.kernel.org/stable/c/b73c1dff8a9d7eeaebabf8097a5b2de192f40913
- https://git.kernel.org/stable/c/0510d1ba0976f97f521feb2b75b0572ea5df3ceb
- https://git.kernel.org/stable/c/383b7270faf42564f133134c2fc3c24bbae52615
- https://git.kernel.org/stable/c/8756b68edae37ff546c02091989a4ceab3f20abd