{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-90246","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-09-11T19:38:34.795Z","datePublished":"2026-09-17T16:07:48.524Z","dateUpdated":"2026-09-18T17:54:09.848Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-09-18T17:54:09.848Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\napparmor: fix integer overflow in verify_tags() bounds check\n\nverify_tags() validates the tagset table unpacked from a policy blob.\nFor each set it reads a count and checks that advancing the index by\nthat count stays inside sets.table[]:\n\n\tu32 cnt = tags->sets.table[i];\n\n\tif (i+cnt >= tags->sets.size) {\n\ni, cnt and sets.size are all u32, so i+cnt is evaluated modulo 2^32.\nsets.table[] is filled by unpack_tagsets() with aa_unpack_u32(), so\nevery entry is a raw unbounded 32-bit word taken from the policy blob,\nand verify_tags() is the function that is supposed to validate it.  A\ncount close to U32_MAX makes the sum wrap to a small value, the guard\npasses, and the inner loop then walks sets.table[++i] past the end of\nthe kcalloc(size, sizeof(u32)) allocation.\n\nNote that sets.size is bounded by 65535, because unpack_tagsets() reads\nit with aa_unpack_array() as a u16, so the wrap cannot be reached by\ngrowing the table; it is reached purely through the attacker-supplied\ncount.\n\nWith sets.size = 2 and sets.table = { 0, 0xffffffff }:\n\n  i = 0: cnt = 0, guard 0 + 0 >= 2 is false, inner loop does not run\n  i = 1: cnt = 0xffffffff, guard (1 + 0xffffffff) mod 2^32 == 0 >= 2 is\n         false, so the guard is bypassed and the inner loop reads\n         sets.table[2] -- one element past a two element allocation\n\nThe walk continues until an out-of-bounds value happens to be >=\nhdrs.size or the access faults, so a crafted policy yields an\nout-of-bounds read on the policy load path\n(aa_replace_profiles -> aa_unpack -> unpack_policydb -> unpack_tags ->\nverify_tags).  unpack_tags() runs before the perms and DFA tables are\nunpacked, so no other table needs to be well formed to reach it.\n\nPolicy load is gated by aa_may_manage_policy(), which checks\nCAP_MAC_ADMIN relative to the subject's own user namespace rather than\nthe init user namespace, so with the default\nunprivileged_userns_apparmor_policy=1 the path is reachable from an\nunprivileged task in a matched-level nested namespace, not only by a\nglobally privileged one.\n\nPerform the addition in u64 so that it cannot wrap, restoring the\nintended i + cnt < sets.size guarantee."}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H","baseScore":7.1,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The overflowing tagset count is a u32 in the policy blob the attacker write()s to /sys/kernel/security/apparmor/.load or .replace (profile_load/profile_replace → policy_update → aa_replace_profiles → aa_unpack → unpack_profile → unpack_pdb → unpack_tags → unpack_tagsets → verify_tags). The malformed word does not arrive in a network protocol message.\nAC:L - unpack_tagsets() stores attacker-chosen u32s from aa_unpack_u32() into sets.table[]; with sets.size=2 and table {0,0xffffffff}, i+cnt wraps modulo 2^32 to 0 so the bounds guard is skipped every time. No race or victim-side state is required.\nPR:L - policy_update() calls aa_may_manage_policy(), which checks CAP_MAC_ADMIN via policy_ns_capable() against subj_cred->user_ns, not init_user_ns. With default unprivileged_userns_apparmor_policy=1, aa_policy_view_capable() permits a uid-0 task whose user_ns->level equals labels_view(label)->level, so unprivileged nested-namespace (container) root can load the crafted blob.\nUI:N - The attacker supplies the packed profile with a tags.sets count of 0xffffffff through their own write to .load/.replace; no other user must mount a volume, open a file, or load policy on their behalf.\nS:U - The OOB read is of the kernel slab object allocated by kcalloc() in unpack_tagsets() while unpacking policy in the host kernel; it does not cross a VM, IOMMU, or other security-authority boundary.\nC:H - After the wrap, verify_tags() executes tags->sets.table[++i] for cnt near U32_MAX, walking u32s past the kcalloc(size,sizeof(u32)) allocation until a value is >= hdrs.size or the access faults. That over-read is not limited to a few bytes.\nI:N - The overflowing loop only reads sets.table[++i] and compares it to hdrs.size; it performs no store through the overflowing index, and aa_unpack() never installs the profile if verify_tags() returns false, oopses, or spins.\nA:H - cnt near U32_MAX causes ~2^32 OOB reads from the sets.table slab object, which oopses when the walk hits unmapped pages; if no OOB word is >= hdrs.size, i wraps and the outer for (i < sets.size) loop in verify_tags() never terminates, hanging the policy-load task."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["security/apparmor/policy_unpack.c"],"versions":[{"version":"3d28e2397af7a89ac3de33c686ed404cda59b5d5","lessThan":"ef79a405f83993f0fda5efde371d98433f7d7a47","status":"affected","versionType":"git"},{"version":"3d28e2397af7a89ac3de33c686ed404cda59b5d5","lessThan":"465946d3c560c0137e6a180ba054dddc4d049f5a","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/policy_unpack.c"],"versions":[{"version":"7.0","status":"affected"},{"version":"0","lessThan":"7.0","status":"unaffected","versionType":"semver"},{"version":"7.2.6","lessThanOrEqual":"7.2.*","status":"unaffected","versionType":"semver"},{"version":"7.3-rc1","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":"7.0","versionEndExcluding":"7.2.6"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.0","versionEndExcluding":"7.3-rc1"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/ef79a405f83993f0fda5efde371d98433f7d7a47"},{"url":"https://git.kernel.org/stable/c/465946d3c560c0137e6a180ba054dddc4d049f5a"}],"title":"apparmor: fix integer overflow in verify_tags() bounds check","x_generator":{"engine":"bippy-1.2.0"}}}}