{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-23407", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-01-13T15:37:46.013Z", "datePublished": "2026-04-01T08:36:37.197Z", "dateUpdated": "2026-08-05T12:21:28.162Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:21:28.162Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\napparmor: fix missing bounds check on DEFAULT table in verify_dfa()\n\nThe verify_dfa() function only checks DEFAULT_TABLE bounds when the state\nis not differentially encoded.\n\nWhen the verification loop traverses the differential encoding chain,\nit reads k = DEFAULT_TABLE[j] and uses k as an array index without\nvalidation. A malformed DFA with DEFAULT_TABLE[j] >= state_count,\ntherefore, causes both out-of-bounds reads and writes.\n\n[ 57.179855] ==================================================================\n[ 57.180549] BUG: KASAN: slab-out-of-bounds in verify_dfa+0x59a/0x660\n[ 57.180904] Read of size 4 at addr ffff888100eadec4 by task su/993\n\n[ 57.181554] CPU: 1 UID: 0 PID: 993 Comm: su Not tainted 6.19.0-rc7-next-20260127 #1 PREEMPT(lazy)\n[ 57.181558] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014\n[ 57.181563] Call Trace:\n[ 57.181572] \n[ 57.181577] dump_stack_lvl+0x5e/0x80\n[ 57.181596] print_report+0xc8/0x270\n[ 57.181605] ? verify_dfa+0x59a/0x660\n[ 57.181608] kasan_report+0x118/0x150\n[ 57.181620] ? verify_dfa+0x59a/0x660\n[ 57.181623] verify_dfa+0x59a/0x660\n[ 57.181627] aa_dfa_unpack+0x1610/0x1740\n[ 57.181629] ? __kmalloc_cache_noprof+0x1d0/0x470\n[ 57.181640] unpack_pdb+0x86d/0x46b0\n[ 57.181647] ? srso_alias_return_thunk+0x5/0xfbef5\n[ 57.181653] ? srso_alias_return_thunk+0x5/0xfbef5\n[ 57.181656] ? aa_unpack_nameX+0x1a8/0x300\n[ 57.181659] aa_unpack+0x20b0/0x4c30\n[ 57.181662] ? srso_alias_return_thunk+0x5/0xfbef5\n[ 57.181664] ? stack_depot_save_flags+0x33/0x700\n[ 57.181681] ? kasan_save_track+0x4f/0x80\n[ 57.181683] ? kasan_save_track+0x3e/0x80\n[ 57.181686] ? __kasan_kmalloc+0x93/0xb0\n[ 57.181688] ? __kvmalloc_node_noprof+0x44a/0x780\n[ 57.181693] ? aa_simple_write_to_buffer+0x54/0x130\n[ 57.181697] ? policy_update+0x154/0x330\n[ 57.181704] aa_replace_profiles+0x15a/0x1dd0\n[ 57.181707] ? srso_alias_return_thunk+0x5/0xfbef5\n[ 57.181710] ? __kvmalloc_node_noprof+0x44a/0x780\n[ 57.181712] ? aa_loaddata_alloc+0x77/0x140\n[ 57.181715] ? srso_alias_return_thunk+0x5/0xfbef5\n[ 57.181717] ? _copy_from_user+0x2a/0x70\n[ 57.181730] policy_update+0x17a/0x330\n[ 57.181733] profile_replace+0x153/0x1a0\n[ 57.181735] ? rw_verify_area+0x93/0x2d0\n[ 57.181740] vfs_write+0x235/0xab0\n[ 57.181745] ksys_write+0xb0/0x170\n[ 57.181748] do_syscall_64+0x8e/0x660\n[ 57.181762] entry_SYSCALL_64_after_hwframe+0x76/0x7e\n[ 57.181765] RIP: 0033:0x7f6192792eb2\n\nRemove the MATCH_FLAG_DIFF_ENCODE condition to validate all DEFAULT_TABLE\nentries unconditionally." } ], "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" }, "scenarios": [ { "lang": "en", "value": "AV:L - The vulnerability is triggered by writing a crafted AppArmor policy to the securityfs interface (`/sys/kernel/security/apparmor/.load` or `.replace`), which requires local system access.\nAC:L - The attacker fully controls the malformed DFA data (DEFAULT_TABLE entries) supplied in the crafted policy. No race conditions or unpredictable conditions are involved — the OOB access is deterministic.\nPR:L - AppArmor policy loading requires CAP_MAC_ADMIN, but the kernel default `unprivileged_userns_apparmor_policy=1` allows this capability to be obtained via unprivileged user namespaces, making it reachable by an unprivileged local user.\nUI:N - No user interaction is required; the attacker can craft and load the malicious AppArmor policy entirely on their own.\nS:U - The vulnerability results in kernel heap corruption within the same security authority (kernel space). No virtualization or sandbox boundary is crossed.\nC:H - The OOB read from `DEFAULT_TABLE(dfa)[j]` and `BASE_TABLE(dfa)[j]` allows reading arbitrary kernel heap memory beyond the allocated DFA tables, enabling kernel address/data disclosure.\nI:H - The OOB write via `BASE_TABLE(dfa)[j] |= MARK_DIFF_ENCODE` corrupts kernel heap memory at attacker-controlled offsets, providing a write primitive that could be leveraged for code execution.\nA:H - The OOB memory access causes kernel oops/crash as demonstrated by the KASAN report, resulting in system denial of service." } ] } ], "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": "031dcc8f4e84fea37dc6f78fdc7288aa7f8386c3", "lessThan": "555829fd91eaf0711e369b0a92aecb0f0aa3281f", "status": "affected", "versionType": "git" }, { "version": "031dcc8f4e84fea37dc6f78fdc7288aa7f8386c3", "lessThan": "a75e12ca90c9e70ba10fee1be2f63cdd63d91a7c", "status": "affected", "versionType": "git" }, { "version": "031dcc8f4e84fea37dc6f78fdc7288aa7f8386c3", "lessThan": "22094c996968a7c5b59cd3fc9fcbdfdd46d02fec", "status": "affected", "versionType": "git" }, { "version": "031dcc8f4e84fea37dc6f78fdc7288aa7f8386c3", "lessThan": "7c7cf05e0606f554c467e3a4dc49e2e578a755b4", "status": "affected", "versionType": "git" }, { "version": "031dcc8f4e84fea37dc6f78fdc7288aa7f8386c3", "lessThan": "76b4d36c5122866452d34d8f79985e191f9c3831", "status": "affected", "versionType": "git" }, { "version": "031dcc8f4e84fea37dc6f78fdc7288aa7f8386c3", "lessThan": "5a68e46dfe0c8c8ffc6f425ebc4cae6238566ecc", "status": "affected", "versionType": "git" }, { "version": "031dcc8f4e84fea37dc6f78fdc7288aa7f8386c3", "lessThan": "f39e126e56c6ec1930fae51ad6bca3dae2a4c3ed", "status": "affected", "versionType": "git" }, { "version": "031dcc8f4e84fea37dc6f78fdc7288aa7f8386c3", "lessThan": "d352873bbefa7eb39995239d0b44ccdf8aaa79a4", "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/555829fd91eaf0711e369b0a92aecb0f0aa3281f" }, { "url": "https://git.kernel.org/stable/c/a75e12ca90c9e70ba10fee1be2f63cdd63d91a7c" }, { "url": "https://git.kernel.org/stable/c/22094c996968a7c5b59cd3fc9fcbdfdd46d02fec" }, { "url": "https://git.kernel.org/stable/c/7c7cf05e0606f554c467e3a4dc49e2e578a755b4" }, { "url": "https://git.kernel.org/stable/c/76b4d36c5122866452d34d8f79985e191f9c3831" }, { "url": "https://git.kernel.org/stable/c/5a68e46dfe0c8c8ffc6f425ebc4cae6238566ecc" }, { "url": "https://git.kernel.org/stable/c/f39e126e56c6ec1930fae51ad6bca3dae2a4c3ed" }, { "url": "https://git.kernel.org/stable/c/d352873bbefa7eb39995239d0b44ccdf8aaa79a4" } ], "title": "apparmor: fix missing bounds check on DEFAULT table in verify_dfa()", "x_generator": { "engine": "bippy-1.2.0" } } } }