{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-22039", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-12-29T08:45:45.809Z", "datePublished": "2025-04-16T14:11:56.975Z", "dateUpdated": "2026-08-05T11:56:12.156Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:56:12.156Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix overflow in dacloffset bounds check\n\nThe dacloffset field was originally typed as int and used in an\nunchecked addition, which could overflow and bypass the existing\nbounds check in both smb_check_perm_dacl() and smb_inherit_dacl().\n\nThis could result in out-of-bounds memory access and a kernel crash\nwhen dereferencing the DACL pointer.\n\nThis patch converts dacloffset to unsigned int and uses\ncheck_add_overflow() to validate access to the DACL." } ], "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; the malicious `dacloffset` arrives in an SMB2 SET_INFO security-descriptor payload over TCP/445 and is triggered by a subsequent SMB2 CREATE. No local access is needed.\nAC:L - The attacker fully controls the 32-bit `dacloffset` field and simply picks a value in 0xFFFFFFF8–0xFFFFFFFF to bypass the check; there is no race, no memory-layout guessing, and the trigger is two ordinary SMB2 requests that can be repeated at will.\nPR:L - The path requires an established SMB2 session and tree connect plus an open handle with write access, so valid (even minimal, non-admin) share credentials are needed — this is squarely post-authentication, not a handshake path.\nUI:N - The attacker plants the crafted security descriptor and re-opens the file entirely on their own; no action by an administrator or any other client is involved.\nS:U - The out-of-bounds access and resulting crash are confined to the kernel's own security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - `pdacl` is dereferenced roughly 4 GiB beyond a small kmalloc'd buffer and the ACE walk then reads further from there — an unbounded kernel-memory read, whose bytes are OR'd into `granted` and returned to the client in the maximal-access create context, and are persisted into on-disk ACLs by smb_inherit_dacl.\nI:H - The out-of-bounds bytes directly determine the DACL verdict and the granted access mask stored in `fp->daccess` (including WRITE_DAC/DELETE/GENERIC_ALL), so the Windows ACL enforcement layer can be defeated, and smb_inherit_dacl writes out-of-bounds heap contents into the security.NTACL xattr of newly created files.\nA:H - Dereferencing a pointer ~4 GiB past the allocation faults on any system where that address is not backed by the direct map, producing a kernel oops in the ksmbd worker (a panic with panic_on_oops); the attacker can repeat it at will." } ] } ], "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": "6a9cd9ff0fa2bcc30b2bfb8bdb161eb20e44b9dc", "status": "affected", "versionType": "git" }, { "version": "0626e6641f6b467447c81dd7678a69c66f7746cf", "lessThan": "6b8d379048b168a0dff5ab1acb975b933f368514", "status": "affected", "versionType": "git" }, { "version": "0626e6641f6b467447c81dd7678a69c66f7746cf", "lessThan": "443b373a4df5a2cb9f7b8c4658b2afedeb16397f", "status": "affected", "versionType": "git" }, { "version": "0626e6641f6b467447c81dd7678a69c66f7746cf", "lessThan": "beff0bc9d69bc8e733f9bca28e2d3df5b3e10e42", "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": "6.12.23", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.13.11", "lessThanOrEqual": "6.13.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.14.2", "lessThanOrEqual": "6.14.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.15", "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": "6.12.23" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.13.11" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.14.2" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.15" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/6a9cd9ff0fa2bcc30b2bfb8bdb161eb20e44b9dc" }, { "url": "https://git.kernel.org/stable/c/6b8d379048b168a0dff5ab1acb975b933f368514" }, { "url": "https://git.kernel.org/stable/c/443b373a4df5a2cb9f7b8c4658b2afedeb16397f" }, { "url": "https://git.kernel.org/stable/c/beff0bc9d69bc8e733f9bca28e2d3df5b3e10e42" } ], "title": "ksmbd: fix overflow in dacloffset bounds check", "x_generator": { "engine": "bippy-1.2.0" } } } }