7.8

CVE-2026-23407: linux Out-of-bounds Read

CVSS: 7.8v3.1HighAnalyzed
AliasesUBUNTU-CVE-2026-23407DEBIAN-CVE-2026-23407
Published 01-04-2026Last modified 05-08-2026
Open JSON

Vulnerability summary

CVE-2026-23407 is a high (CVSS 7.8) Out-of-bounds Read vulnerability in linux. EPSS estimates a 0.18% chance of exploitation in the next 30 days, higher than 7.3% of scored vulnerabilities.

Overall risk
31/100
0100
Medium · default modelHow is this calculated?
CVSS score
7.8/10
010
High · v3.1 (CVE.org)
EPSS score
0.18%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 13 · Related 13
SUSE-SU-2026:21834-1SUSE-SU-2026:2195-1SUSE-SU-2026:2238-1USN-8098-10USN-8152-1USN-8163-1

Timeline

  1. 01-04-2026
    PublishedVulnerability first disclosed.
  2. 05-08-2026
    Last modifiedVulnerability information updated.

Description

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 metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.18%

Chance of exploitation in the next 30 days

Percentile

7%

Versus all other CVEs

30-day change

0.00 pp

From 0.18% on 21-09-2026

21-09-202621-10-2026
EPSS score
0.18%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Ubuntu152 products
  • linux< 5.4.0-227.247 | < 5.15.0-173.183 | < 6.8.0-106.106 | < 6.17.0-19.19
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-aws< 5.4.0-1156.166 | < 5.15.0-1103.110 | < 6.8.0-1050.53 | < 6.17.0-1009.9
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Linux2 products
  • linux≥ 031dcc8f4e84fea37dc6f78fdc7288aa7f8386c3, < 555829fd91eaf0711e369b0a92aecb0f0aa3281f | ≥ 031dcc8f4e84fea37dc6f78fdc7288aa7f8386c3, < a75e12ca90c9e70ba10fee1be2f63cdd63d91a7c | ≥ 031dcc8f4e84fea37dc6f78fdc7288aa7f8386c3, < 22094c996968a7c5b59cd3fc9fcbdfdd46d02fec | ≥ 031dcc8f4e84fea37dc6f78fdc7288aa7f8386c3, < 7c7cf05e0606f554c467e3a4dc49e2e578a755b4 | ≥ 031dcc8f4e84fea37dc6f78fdc7288aa7f8386c3, < 76b4d36c5122866452d34d8f79985e191f9c3831 | ≥ 031dcc8f4e84fea37dc6f78fdc7288aa7f8386c3, < 5a68e46dfe0c8c8ffc6f425ebc4cae6238566ecc | ≥ 031dcc8f4e84fea37dc6f78fdc7288aa7f8386c3, < f39e126e56c6ec1930fae51ad6bca3dae2a4c3ed | ≥ 031dcc8f4e84fea37dc6f78fdc7288aa7f8386c3, < d352873bbefa7eb39995239d0b44ccdf8aaa79a4 | 4.17
  • linux_kernel≥ 4.17.1, < 5.10.253 | ≥ 5.11, < 5.15.203 | ≥ 5.16, < 6.1.169 | ≥ 6.2, < 6.6.130 | ≥ 6.7, < 6.12.77 | ≥ 6.13, < 6.18.18 | ≥ 6.19, < 6.19.8 | 4.17 | 7.0:rc1 | 7.0:rc2 | 7.0:rc3 | 7.0:rc4 | 7.0:rc5 | 7.0:rc6 | 7.0:rc7
Debian1 product
  • linux< 6.1.164-1 | < 6.12.74-2 | < 6.19.6-2

3 vendors · 155 products

References

26 links
Show all 26 references