High 7.8Published Apr 1, 2026

CVE-2026-23407apparmor: fix missing bounds check on DEFAULT table in verify_dfa()

Updated under an hour ago (Oct 27, 2026, 8:10 AM ET)

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In the Linux kernel, the following vulnerability has been resolved: apparmor: fix missing bounds check on DEFAULT table in verify_dfa() The verify_dfa() function only checks DEFAULT_TABLE bounds when the state is not differentially encoded. When the verification loop traverses the differential encoding chain, it reads k = DEFAULT_TABLE[j] and uses k as an array index without validation. A malformed DFA with DEFAULT_TABLE[j] >= state_count, therefore, causes both out-of-bounds reads and writes. [ 57.179855] ================================================================== [ 57.180549] BUG: KASAN: slab-out-of-bounds in verify_dfa+0x59a/0x660 [ 57.180904] Read of size 4 at addr ffff888100eadec4 by task su/993 [ 57.181554] CPU: 1 UID: 0 PID: 993 Comm: su Not tainted 6.19.0-rc7-next-20260127 #1 PREEMPT(lazy) [ 57.181558] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 57.181563] Call Trace: [ 57.181572] <TASK> [ 57.181577] dump_stack_lvl+0x5e/0x80 [ 57.181596] print_report+0xc8/0x270 [ 57.181605] ? verify_dfa+0x59a/0x660 [ 57.181608] kasan_report+0x118/0x150 [ 57.181620] ? verify_dfa+0x59a/0x660 [ 57.181623] verify_dfa+0x59a/0x660 [ 57.181627] aa_dfa_unpack+0x1610/0x1740 [ 57.181629] ? __kmalloc_cache_noprof+0x1d0/0x470 [ 57.181640] unpack_pdb+0x86d/0x46b0 [ 57.181647] ? srso_alias_return_thunk+0x5/0xfbef5 [ 57.181653] ? srso_alias_return_thunk+0x5/0xfbef5 [ 57.181656] ? aa_unpack_nameX+0x1a8/0x300 [ 57.181659] aa_unpack+0x20b0/0x4c30 [ 57.181662] ? srso_alias_return_thunk+0x5/0xfbef5 [ 57.181664] ? stack_depot_save_flags+0x33/0x700 [ 57.181681] ? kasan_save_track+0x4f/0x80 [ 57.181683] ? kasan_save_track+0x3e/0x80 [ 57.181686] ? __kasan_kmalloc+0x93/0xb0 [ 57.181688] ? __kvmalloc_node_noprof+0x44a/0x780 [ 57.181693] ? aa_simple_write_to_buffer+0x54/0x130 [ 57.181697] ? policy_update+0x154/0x330 [ 57.181704] aa_replace_profiles+0x15a/0x1dd0 [ 57.181707] ? srso_alias_return_thunk+0x5/0xfbef5 [ 57.181710] ? __kvmalloc_node_noprof+0x44a/0x780 [ 57.181712] ? aa_loaddata_alloc+0x77/0x140 [ 57.181715] ? srso_alias_return_thunk+0x5/0xfbef5 [ 57.181717] ? _copy_from_user+0x2a/0x70 [ 57.181730] policy_update+0x17a/0x330 [ 57.181733] profile_replace+0x153/0x1a0 [ 57.181735] ? rw_verify_area+0x93/0x2d0 [ 57.181740] vfs_write+0x235/0xab0 [ 57.181745] ksys_write+0xb0/0x170 [ 57.181748] do_syscall_64+0x8e/0x660 [ 57.181762] entry_SYSCALL_64_after_hwframe+0x76/0x7e [ 57.181765] RIP: 0033:0x7f6192792eb2 Remove the MATCH_FLAG_DIFF_ENCODE condition to validate all DEFAULT_TABLE entries unconditionally.

CVSS: 7.8 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE): Not given
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Analyzed
Record last updated: Aug 5, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	from 031dcc8f4e84fea37dc6f78fdc7288aa7f8386c3 before 555829fd91eaf0711e369b0a92aecb0f0aa3281f; from 031dcc8f4e84fea37dc6f78fdc7288aa7f8386c3 before a75e12ca90c9e70ba10fee1be2f63cdd63d91a7c; from 031dcc8f4e84fea37dc6f78fdc7288aa7f8386c3 before 22094c996968a7c5b59cd3fc9fcbdfdd46d02fec; 031dcc8f4e84fea37dc6f78fdc7288aa7f8386c3 builds before 7c7cf05e0606f554c467e3a4dc49e2e578a755b4; from 031dcc8f4e84fea37dc6f78fdc7288aa7f8386c3 before 76b4d36c5122866452d34d8f79985e191f9c3831; 031dcc8f4e84fea37dc6f78fdc7288aa7f8386c3 builds before 5a68e46dfe0c8c8ffc6f425ebc4cae6238566ecc; from 031dcc8f4e84fea37dc6f78fdc7288aa7f8386c3 before f39e126e56c6ec1930fae51ad6bca3dae2a4c3ed; from 031dcc8f4e84fea37dc6f78fdc7288aa7f8386c3 before d352873bbefa7eb39995239d0b44ccdf8aaa79a4	CNA record
linux linux_kernel linux:linux_kernel	from 4.17.1 before 5.10.253; from 5.11 before 5.15.203; from 5.16 before 6.1.169; from 6.2 before 6.6.130; from 6.7 before 6.12.77; from 6.13 before 6.18.18; from 6.19 before 6.19.8; 4.17; and 7 more ranges	NVD

References

References

https://git.kernel.org/stable/c/555829fd91eaf0711e369b0a92aecb0f0aa3281f	patch
https://git.kernel.org/stable/c/a75e12ca90c9e70ba10fee1be2f63cdd63d91a7c	patch
https://git.kernel.org/stable/c/22094c996968a7c5b59cd3fc9fcbdfdd46d02fec	patch
https://git.kernel.org/stable/c/7c7cf05e0606f554c467e3a4dc49e2e578a755b4	patch
https://git.kernel.org/stable/c/76b4d36c5122866452d34d8f79985e191f9c3831	patch
https://git.kernel.org/stable/c/5a68e46dfe0c8c8ffc6f425ebc4cae6238566ecc	patch
https://git.kernel.org/stable/c/f39e126e56c6ec1930fae51ad6bca3dae2a4c3ed	patch
https://git.kernel.org/stable/c/d352873bbefa7eb39995239d0b44ccdf8aaa79a4	patch

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.