{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-31432", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-03-09T15:48:24.089Z", "datePublished": "2026-04-22T08:15:10.873Z", "dateUpdated": "2026-08-05T12:22:26.699Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:22:26.699Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix OOB write in QUERY_INFO for compound requests\n\nWhen a compound request such as READ + QUERY_INFO(Security) is received,\nand the first command (READ) consumes most of the response buffer,\nksmbd could write beyond the allocated buffer while building a security\ndescriptor.\n\nThe root cause was that smb2_get_info_sec() checked buffer space using\nppntsd_size from xattr, while build_sec_desc() often synthesized a\nsignificantly larger descriptor from POSIX ACLs.\n\nThis patch introduces smb_acl_sec_desc_scratch_len() to accurately\ncompute the final descriptor size beforehand, performs proper buffer\nchecking with smb2_calc_max_out_buf_len(), and uses exact-sized\nallocation + iov pinning." } ], "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, directly reachable over the network by any remote SMB client.\nAC:L - The attacker reliably triggers the OOB write by crafting a compound request (e.g., READ + QUERY_INFO(Security)) where the first command consumes most of the response buffer. No race condition or special conditions are needed.\nPR:L - The QUERY_INFO command requires a valid SMB session (checked by smb2_check_user_session), a tree connect, and an open file handle. Even guest access requires completing session setup, so low privileges are needed.\nUI:N - No user interaction is required; the attacker sends the compound request directly to the ksmbd server.\nS:U - The vulnerability results in kernel heap corruption within the same security authority (the kernel); no security boundary such as a VM or sandbox is crossed.\nC:H - The heap buffer overflow writes past the kvzalloc'd response buffer into adjacent kernel heap objects. This OOB write can be leveraged to corrupt adjacent structures and create information disclosure primitives.\nI:H - The OOB write corrupts kernel heap memory with attacker-influenced data (security descriptor content including SIDs and ACEs derived from file ACLs), enabling potential control flow hijacking or arbitrary write primitives.\nA:H - The heap buffer overflow corrupts adjacent kernel data structures, reliably causing kernel crashes or panics." } ] } ], "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", "fs/smb/server/smbacl.c", "fs/smb/server/smbacl.h" ], "versions": [ { "version": "e2b76ab8b5c9327ab2dae6da05d0752eb2f4771d", "lessThan": "850452af77f55d185f9445e1f7a1db53c5e4aad4", "status": "affected", "versionType": "git" }, { "version": "e2b76ab8b5c9327ab2dae6da05d0752eb2f4771d", "lessThan": "d48c64fb80ad78b3dd29fb7d79b6ec7bd72bfc09", "status": "affected", "versionType": "git" }, { "version": "e2b76ab8b5c9327ab2dae6da05d0752eb2f4771d", "lessThan": "075ea208c648cc2bcd616295b711d3637c61de45", "status": "affected", "versionType": "git" }, { "version": "e2b76ab8b5c9327ab2dae6da05d0752eb2f4771d", "lessThan": "515c2daab46021221bdf406bef19bc90a44ec617", "status": "affected", "versionType": "git" }, { "version": "e2b76ab8b5c9327ab2dae6da05d0752eb2f4771d", "lessThan": "fda9522ed6afaec45cabc198d8492270c394c7bc", "status": "affected", "versionType": "git" }, { "version": "f2283680a80571ca82d710bc6ecd8f8beac67d63", "status": "affected", "versionType": "git" }, { "version": "9f297df20d93411c0b4ddad7f88ba04a7cd36e77", "status": "affected", "versionType": "git" }, { "version": "5.15.145", "lessThan": "5.16", "status": "affected", "versionType": "semver" }, { "version": "6.1.71", "lessThan": "6.2", "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", "fs/smb/server/smbacl.c", "fs/smb/server/smbacl.h" ], "versions": [ { "version": "6.6", "status": "affected" }, { "version": "0", "lessThan": "6.6", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.143", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.81", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.22", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.19.12", "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": "6.6", "versionEndExcluding": "6.6.143" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.6", "versionEndExcluding": "6.12.81" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.6", "versionEndExcluding": "6.18.22" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.6", "versionEndExcluding": "6.19.12" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.6", "versionEndExcluding": "7.0" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15.145" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1.71" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/850452af77f55d185f9445e1f7a1db53c5e4aad4" }, { "url": "https://git.kernel.org/stable/c/d48c64fb80ad78b3dd29fb7d79b6ec7bd72bfc09" }, { "url": "https://git.kernel.org/stable/c/075ea208c648cc2bcd616295b711d3637c61de45" }, { "url": "https://git.kernel.org/stable/c/515c2daab46021221bdf406bef19bc90a44ec617" }, { "url": "https://git.kernel.org/stable/c/fda9522ed6afaec45cabc198d8492270c394c7bc" } ], "title": "ksmbd: fix OOB write in QUERY_INFO for compound requests", "x_generator": { "engine": "bippy-1.2.0" } } } }