{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-21946","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2024-12-29T08:45:45.790Z","datePublished":"2025-04-01T15:41:08.955Z","dateUpdated":"2026-08-05T11:55:31.476Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T11:55:31.476Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix out-of-bounds in parse_sec_desc()\n\nIf osidoffset, gsidoffset and dacloffset could be greater than smb_ntsd\nstruct size. If it is smaller, It could cause slab-out-of-bounds.\nAnd when validating sid, It need to check it included subauth array size."}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":8.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:N - ksmbd is the in-kernel SMB server listening on TCP/445, and every field driving the bug (osidoffset/gsidoffset/dacloffset, num_subauth, BufferLength) comes directly from a remote client's SMB2_SET_INFO or SMB2_CREATE PDU. No local access is required.\nAC:L - The attacker fully controls the security-descriptor offsets, num_subauth, and the total PDU size, so the out-of-bounds access is deterministic on every request; no race, timing window, or uncontrollable memory-layout condition is involved.\nPR:L - The path requires an established SMB session and a tree connect with KSMBD_TREE_CONN_FLAG_WRITABLE plus an open file handle, so a low-privileged share user (or a guest account where \"map to guest\" is configured) suffices — no administrative rights on the target.\nUI:N - The attacker drives the entire sequence (negotiate, session setup, tree connect, create, set-info) from its own client; no action by any local user or administrator is needed.\nS:U - The out-of-bounds access occurs in the ksmbd kernel thread and its consequences stay within the kernel's own security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - The read runs up to ~60 bytes past the request buffer at an attacker-chosen offset, and the leaked 32-bit word is written into the file's owner uid/gid and read straight back via SMB2_QUERY_INFO security, producing a repeatable remote heap-disclosure oracle (compare_sids() on the owner SID gives a second oracle) that can be aimed at sprayed adjacent objects containing pointers or other clients' data.\nI:H - Out-of-bounds kernel memory directly determines security-relevant persistent state — notify_change() sets the file's owner uid/gid and set_posix_acl()/mode are derived from the same unvalidated SID data — so the attacker causes modification of filesystem ownership and permission metadata from memory outside the intended object.\nA:H - With ~4 MB PDUs the request buffer is vmalloc-backed, and the attacker can size it so the allocation ends exactly on a page boundary, making the sub_auth[] read hit the vmalloc guard page and oops the ksmbd kernel thread; on KASAN/hardened builds the slab-out-of-bounds report panics the machine outright."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/server/smbacl.c"],"versions":[{"version":"0626e6641f6b467447c81dd7678a69c66f7746cf","lessThan":"f4ee19528664777af8b842f8f001be98345aa973","status":"affected","versionType":"git"},{"version":"0626e6641f6b467447c81dd7678a69c66f7746cf","lessThan":"c1569dbbe2d43041be9f3fef7ca08bec3b66ad1b","status":"affected","versionType":"git"},{"version":"0626e6641f6b467447c81dd7678a69c66f7746cf","lessThan":"159d059cbcb0e6d0e7a7b34af3862ba09a6b22d1","status":"affected","versionType":"git"},{"version":"0626e6641f6b467447c81dd7678a69c66f7746cf","lessThan":"6a9831180d0b23b5c97e2bd841aefc8f82900172","status":"affected","versionType":"git"},{"version":"0626e6641f6b467447c81dd7678a69c66f7746cf","lessThan":"d6e13e19063db24f94b690159d0633aaf72a0f03","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/server/smbacl.c"],"versions":[{"version":"5.15","status":"affected"},{"version":"0","lessThan":"5.15","status":"unaffected","versionType":"semver"},{"version":"6.1.160","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.83","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.19","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.13.7","lessThanOrEqual":"6.13.*","status":"unaffected","versionType":"semver"},{"version":"6.14","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":"5.15","versionEndExcluding":"6.1.160"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15","versionEndExcluding":"6.6.83"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15","versionEndExcluding":"6.12.19"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15","versionEndExcluding":"6.13.7"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15","versionEndExcluding":"6.14"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/f4ee19528664777af8b842f8f001be98345aa973"},{"url":"https://git.kernel.org/stable/c/c1569dbbe2d43041be9f3fef7ca08bec3b66ad1b"},{"url":"https://git.kernel.org/stable/c/159d059cbcb0e6d0e7a7b34af3862ba09a6b22d1"},{"url":"https://git.kernel.org/stable/c/6a9831180d0b23b5c97e2bd841aefc8f82900172"},{"url":"https://git.kernel.org/stable/c/d6e13e19063db24f94b690159d0633aaf72a0f03"}],"title":"ksmbd: fix out-of-bounds in parse_sec_desc()","x_generator":{"engine":"bippy-1.2.0"}}}}