{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-31478", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-03-09T15:48:24.098Z", "datePublished": "2026-04-22T13:54:06.157Z", "dateUpdated": "2026-08-05T12:22:57.123Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:22:57.123Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: replace hardcoded hdr2_len with offsetof() in smb2_calc_max_out_buf_len()\n\nAfter this commit (e2b76ab8b5c9 \"ksmbd: add support for read compound\"),\nresponse buffer management was changed to use dynamic iov array.\nIn the new design, smb2_calc_max_out_buf_len() expects the second\nargument (hdr2_len) to be the offset of ->Buffer field in the\nresponse structure, not a hardcoded magic number.\nFix the remaining call sites to use the correct offsetof() value." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 9.8, "baseSeverity": "CRITICAL" }, "scenarios": [ { "lang": "en", "value": "AV:N - The vulnerable code is in ksmbd SMB2 request handling reachable over TCP SMB connections, including normal network-facing port 445 deployments.\nAC:L - An attacker controls the SMB2 compound request layout, output buffer lengths, and command sequence needed to reach the miscalculation; no race or external timing condition is required.\nPR:N - The handlers run after SMB session/tree setup, but ksmbd supports guest/anonymous sessions and guest shares, so a reasonable deployment allows a remote attacker to reach the path without credentials.\nUI:N - No victim action is required after the ksmbd service is exposed; the attacker sends crafted SMB2 requests directly.\nS:U - The impact remains within the kernel/ksmbd security authority and does not cross a VM, IOMMU, or sandbox boundary.\nC:H - The bug can cause out-of-bounds kernel response-buffer memory corruption in compound SMB2 handling, which is defensibly treatable as exploitable memory corruption with potential information disclosure.\nI:H - The incorrect length calculation can permit an out-of-bounds write past the ksmbd response buffer, and kernel OOB writes are scored as high integrity impact.\nA:H - Even if not weaponized for code execution, the out-of-bounds kernel write can crash or oops the kernel, causing high availability impact." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/smb/server/smb2pdu.c" ], "versions": [ { "version": "f2283680a80571ca82d710bc6ecd8f8beac67d63", "lessThan": "70b4c414889492c522b6e4331562360f49be2361", "status": "affected", "versionType": "git" }, { "version": "9f297df20d93411c0b4ddad7f88ba04a7cd36e77", "lessThan": "9a7166f0ef8cbb7bb48dd05e2471d995566003f5", "status": "affected", "versionType": "git" }, { "version": "e2b76ab8b5c9327ab2dae6da05d0752eb2f4771d", "lessThan": "c3a89e3ec1ccf64fa6a34e391e1581ebbcba8683", "status": "affected", "versionType": "git" }, { "version": "e2b76ab8b5c9327ab2dae6da05d0752eb2f4771d", "lessThan": "6aef1765d6807e0f027cd87f6ac973eb0879a46d", "status": "affected", "versionType": "git" }, { "version": "e2b76ab8b5c9327ab2dae6da05d0752eb2f4771d", "lessThan": "80824c7e527b70cf9039534e60aff592e8f209d1", "status": "affected", "versionType": "git" }, { "version": "e2b76ab8b5c9327ab2dae6da05d0752eb2f4771d", "lessThan": "4cb537ae4f37d7d0f617815ed4bed7173fb50861", "status": "affected", "versionType": "git" }, { "version": "e2b76ab8b5c9327ab2dae6da05d0752eb2f4771d", "lessThan": "0e55f63dd08f09651d39e1b709a91705a8a0ddcb", "status": "affected", "versionType": "git" }, { "version": "5.15.145", "lessThan": "5.15.203", "status": "affected", "versionType": "semver" }, { "version": "6.1.71", "lessThan": "6.1.168", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/smb/server/smb2pdu.c" ], "versions": [ { "version": "6.6", "status": "affected" }, { "version": "0", "lessThan": "6.6", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.203", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.168", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.131", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.80", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.21", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.19.11", "lessThanOrEqual": "6.19.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.0", "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": "5.15.145", "versionEndExcluding": "5.15.203" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1.71", "versionEndExcluding": "6.1.168" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.6", "versionEndExcluding": "6.6.131" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.6", "versionEndExcluding": "6.12.80" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.6", "versionEndExcluding": "6.18.21" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.6", "versionEndExcluding": "6.19.11" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.6", "versionEndExcluding": "7.0" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/70b4c414889492c522b6e4331562360f49be2361" }, { "url": "https://git.kernel.org/stable/c/9a7166f0ef8cbb7bb48dd05e2471d995566003f5" }, { "url": "https://git.kernel.org/stable/c/c3a89e3ec1ccf64fa6a34e391e1581ebbcba8683" }, { "url": "https://git.kernel.org/stable/c/6aef1765d6807e0f027cd87f6ac973eb0879a46d" }, { "url": "https://git.kernel.org/stable/c/80824c7e527b70cf9039534e60aff592e8f209d1" }, { "url": "https://git.kernel.org/stable/c/4cb537ae4f37d7d0f617815ed4bed7173fb50861" }, { "url": "https://git.kernel.org/stable/c/0e55f63dd08f09651d39e1b709a91705a8a0ddcb" } ], "title": "ksmbd: replace hardcoded hdr2_len with offsetof() in smb2_calc_max_out_buf_len()", "x_generator": { "engine": "bippy-1.2.0" } } } }