{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-89761", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.764Z", "datePublished": "2026-09-11T19:47:02.837Z", "dateUpdated": "2026-10-19T08:52:14.804Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T08:52:14.804Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\napparmor: fix out-of-bounds write when null terminating a label vec\n\naa_vec_unique() null terminates at vec[n - dups] when VEC_FLAG_TERMINATE\nis passed. If the components are all distinct no duplicates are dropped,\ndups is 0 and the terminator goes to vec[n], so the caller has to provide\nroom for n + 1 entries.\n\naa_label_strn_parse() sets up its vector with vec_setup(profile, vec, len,\ngfp) and then calls aa_vec_unique(vec, len, VEC_FLAG_TERMINATE), but\nvec_setup() does not reserve the terminator entry. Up to LOCAL_VEC_ENTRIES\nit uses the local array of LOCAL_VEC_ENTRIES pointers, above that it\nallocates exactly len pointers. The terminator therefore lands one entry\npast the end of the local array when len is LOCAL_VEC_ENTRIES, and one\nentry past the end of the allocation when len is larger.\n\nlen comes from the number of \"//&\" separated components in the label name\nand label_count_strn_entries() does not bound it. An unprivileged task\nreaches the parse by writing to /proc/self/attr/apparmor/current or through\nlsm_set_self_attr(2), both of which go through do_setattr(), and the name\nis parsed before the change_profile permission is checked.\nThe query_label() path behind the securityfs .access file, which is\nmode 0666, performs no permission check at all. Every component has to\nresolve to a loaded profile, so a system with policy loaded is required.\n\nThe other two VEC_FLAG_TERMINATE users work on a label vec that\naa_label_alloc() has already sized with \"+ 1 for null terminator entry on\nvec\". Reserve the same entry in vec_setup() and DEFINE_VEC(). Passing\nlen + 1 from the caller instead would move len == LOCAL_VEC_ENTRIES out of\nthe local array and into kzalloc()." } ], "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 - An unprivileged local process reaches aa_label_strn_parse() by writing a compound label to /sys/kernel/security/apparmor/.access (mode 0666) via query_label()/query_data(), or via /proc/self/attr/apparmor/current and lsm_set_self_attr(2) through do_setattr(); there is no network-facing path.\nAC:L - The attacker fully controls the \"//&\"-separated label string and thus the vector length; when at least eight distinct profiles are loaded (typical Ubuntu/Debian/SUSE policy, or attacker-loaded via user namespaces) with no duplicates, aa_vec_unique() deterministically writes NULL one pointer past the stack array or heap allocation, with no race.\nPR:L - query_label() on the world-writable .access file performs no capability or change_profile check, and do_setattr() parses the name before AA_MAY_CHANGE_PROFILE is tested, so a basic unprivileged local user suffices; real root is not required.\nUI:N - The attacker opens and writes the .access query or their own procattr themselves; no victim action such as mounting a filesystem or opening a file is required.\nS:U - The out-of-bounds write corrupts kernel stack or heap within the same kernel security authority. This is standard local privilege-escalation impact, not a VM escape or IOMMU/sandbox boundary crossing.\nC:H - The one-pointer out-of-bounds write lands in adjacent stack locals or the next kmalloc object. With attacker-chosen allocation size (component count) for heap grooming, that corruption can be leveraged as a kernel memory-disclosure primitive, so confidentiality impact is high.\nI:H - aa_vec_unique() writes a NULL pointer one slot past a LOCAL_VEC_ENTRIES stack array or a heap buffer sized exactly to the attacker-chosen component count. An out-of-bounds write that corrupts adjacent kernel objects is a write primitive suitable for control-flow hijacking.\nA:H - Corrupting an adjacent stack pointer, heap object, or stack canary can oops, panic, or hang the kernel; the unexploited NULL write alone is sufficient for 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/include/label.h" ], "versions": [ { "version": "f1bd904175e8190ce14aedee37e207ab51fe3b30", "lessThan": "9124e078ea2250d8d01d2162a550acb01ef5bf48", "status": "affected", "versionType": "git" }, { "version": "f1bd904175e8190ce14aedee37e207ab51fe3b30", "lessThan": "28069434aef66b9d084f0609b7a29c171846815e", "status": "affected", "versionType": "git" }, { "version": "f1bd904175e8190ce14aedee37e207ab51fe3b30", "lessThan": "36bdd0b45ec3f4822832a56e9db8674c8450dfce", "status": "affected", "versionType": "git" }, { "version": "f1bd904175e8190ce14aedee37e207ab51fe3b30", "lessThan": "9f1e40193eef7f047e6b77cfb4b4cafdecd7a123", "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/include/label.h" ], "versions": [ { "version": "4.13", "status": "affected" }, { "version": "0", "lessThan": "4.13", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.109", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.50", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.4", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.3", "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": "4.13", "versionEndExcluding": "6.12.109" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.13", "versionEndExcluding": "6.18.50" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.13", "versionEndExcluding": "7.2.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.13", "versionEndExcluding": "7.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/9124e078ea2250d8d01d2162a550acb01ef5bf48" }, { "url": "https://git.kernel.org/stable/c/28069434aef66b9d084f0609b7a29c171846815e" }, { "url": "https://git.kernel.org/stable/c/36bdd0b45ec3f4822832a56e9db8674c8450dfce" }, { "url": "https://git.kernel.org/stable/c/9f1e40193eef7f047e6b77cfb4b4cafdecd7a123" } ], "title": "apparmor: fix out-of-bounds write when null terminating a label vec", "x_generator": { "engine": "bippy-1.2.0" } } } }