{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-23406","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-01-13T15:37:46.013Z","datePublished":"2026-04-01T08:36:36.460Z","dateUpdated":"2026-05-11T22:06:17.660Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-05-11T22:06:17.660Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\napparmor: fix side-effect bug in match_char() macro usage\n\nThe match_char() macro evaluates its character parameter multiple\ntimes when traversing differential encoding chains. When invoked\nwith *str++, the string pointer advances on each iteration of the\ninner do-while loop, causing the DFA to check different characters\nat each iteration and therefore skip input characters.\nThis results in out-of-bounds reads when the pointer advances past\nthe input buffer boundary.\n\n[   94.984676] ==================================================================\n[   94.985301] BUG: KASAN: slab-out-of-bounds in aa_dfa_match+0x5ae/0x760\n[   94.985655] Read of size 1 at addr ffff888100342000 by task file/976\n\n[   94.986319] CPU: 7 UID: 1000 PID: 976 Comm: file Not tainted 6.19.0-rc7-next-20260127 #1 PREEMPT(lazy)\n[   94.986322] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014\n[   94.986329] Call Trace:\n[   94.986341]  <TASK>\n[   94.986347]  dump_stack_lvl+0x5e/0x80\n[   94.986374]  print_report+0xc8/0x270\n[   94.986384]  ? aa_dfa_match+0x5ae/0x760\n[   94.986388]  kasan_report+0x118/0x150\n[   94.986401]  ? aa_dfa_match+0x5ae/0x760\n[   94.986405]  aa_dfa_match+0x5ae/0x760\n[   94.986408]  __aa_path_perm+0x131/0x400\n[   94.986418]  aa_path_perm+0x219/0x2f0\n[   94.986424]  apparmor_file_open+0x345/0x570\n[   94.986431]  security_file_open+0x5c/0x140\n[   94.986442]  do_dentry_open+0x2f6/0x1120\n[   94.986450]  vfs_open+0x38/0x2b0\n[   94.986453]  ? may_open+0x1e2/0x2b0\n[   94.986466]  path_openat+0x231b/0x2b30\n[   94.986469]  ? __x64_sys_openat+0xf8/0x130\n[   94.986477]  do_file_open+0x19d/0x360\n[   94.986487]  do_sys_openat2+0x98/0x100\n[   94.986491]  __x64_sys_openat+0xf8/0x130\n[   94.986499]  do_syscall_64+0x8e/0x660\n[   94.986515]  ? count_memcg_events+0x15f/0x3c0\n[   94.986526]  ? srso_alias_return_thunk+0x5/0xfbef5\n[   94.986540]  ? handle_mm_fault+0x1639/0x1ef0\n[   94.986551]  ? vma_start_read+0xf0/0x320\n[   94.986558]  ? srso_alias_return_thunk+0x5/0xfbef5\n[   94.986561]  ? srso_alias_return_thunk+0x5/0xfbef5\n[   94.986563]  ? fpregs_assert_state_consistent+0x50/0xe0\n[   94.986572]  ? srso_alias_return_thunk+0x5/0xfbef5\n[   94.986574]  ? arch_exit_to_user_mode_prepare+0x9/0xb0\n[   94.986587]  ? srso_alias_return_thunk+0x5/0xfbef5\n[   94.986588]  ? irqentry_exit+0x3c/0x590\n[   94.986595]  entry_SYSCALL_64_after_hwframe+0x76/0x7e\n[   94.986597] RIP: 0033:0x7fda4a79c3ea\n\nFix by extracting the character value before invoking match_char,\nensuring single evaluation per outer loop."}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"}}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["security/apparmor/match.c"],"versions":[{"version":"074c1cd798cb0b481d7eaa749b64aa416563c053","lessThan":"c7dc56d8b37eda1396feeec3ab1c7ecee5eae31b","status":"affected","versionType":"git"},{"version":"074c1cd798cb0b481d7eaa749b64aa416563c053","lessThan":"f16f2e5936c0f5f0d11fdf10d2be3e47e7108e42","status":"affected","versionType":"git"},{"version":"074c1cd798cb0b481d7eaa749b64aa416563c053","lessThan":"1fc94f16098213d01e56c97feed9b3ecf0147a37","status":"affected","versionType":"git"},{"version":"074c1cd798cb0b481d7eaa749b64aa416563c053","lessThan":"5a184f7cbdeaad17e16dedf3c17d0cd622edfed8","status":"affected","versionType":"git"},{"version":"074c1cd798cb0b481d7eaa749b64aa416563c053","lessThan":"b73c1dff8a9d7eeaebabf8097a5b2de192f40913","status":"affected","versionType":"git"},{"version":"074c1cd798cb0b481d7eaa749b64aa416563c053","lessThan":"0510d1ba0976f97f521feb2b75b0572ea5df3ceb","status":"affected","versionType":"git"},{"version":"074c1cd798cb0b481d7eaa749b64aa416563c053","lessThan":"383b7270faf42564f133134c2fc3c24bbae52615","status":"affected","versionType":"git"},{"version":"074c1cd798cb0b481d7eaa749b64aa416563c053","lessThan":"8756b68edae37ff546c02091989a4ceab3f20abd","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["security/apparmor/match.c"],"versions":[{"version":"4.17","status":"affected"},{"version":"0","lessThan":"4.17","status":"unaffected","versionType":"semver"},{"version":"5.10.253","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.15.203","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.169","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.130","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.77","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.18","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"6.19.8","lessThanOrEqual":"6.19.*","status":"unaffected","versionType":"semver"},{"version":"7.0","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.17","versionEndExcluding":"5.10.253"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.17","versionEndExcluding":"5.15.203"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.17","versionEndExcluding":"6.1.169"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.17","versionEndExcluding":"6.6.130"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.17","versionEndExcluding":"6.12.77"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.17","versionEndExcluding":"6.18.18"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.17","versionEndExcluding":"6.19.8"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.17","versionEndExcluding":"7.0"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/c7dc56d8b37eda1396feeec3ab1c7ecee5eae31b"},{"url":"https://git.kernel.org/stable/c/f16f2e5936c0f5f0d11fdf10d2be3e47e7108e42"},{"url":"https://git.kernel.org/stable/c/1fc94f16098213d01e56c97feed9b3ecf0147a37"},{"url":"https://git.kernel.org/stable/c/5a184f7cbdeaad17e16dedf3c17d0cd622edfed8"},{"url":"https://git.kernel.org/stable/c/b73c1dff8a9d7eeaebabf8097a5b2de192f40913"},{"url":"https://git.kernel.org/stable/c/0510d1ba0976f97f521feb2b75b0572ea5df3ceb"},{"url":"https://git.kernel.org/stable/c/383b7270faf42564f133134c2fc3c24bbae52615"},{"url":"https://git.kernel.org/stable/c/8756b68edae37ff546c02091989a4ceab3f20abd"}],"title":"apparmor: fix side-effect bug in match_char() macro usage","x_generator":{"engine":"bippy-1.2.0"}}}}