{ "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" } } } }