{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-98405", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-25T10:25:14.347Z", "datePublished": "2026-10-14T13:27:40.589Z", "dateUpdated": "2026-10-24T14:08:44.159Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-24T14:08:44.159Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix missing iov bounds check in parse_posix_sids()\n\nIn parse_posix_sids(), sidsbuf_end is calculated using the server-supplied\nout_len without being validated against the actual length of the received\niov (iov_len).\n\nIf a server provides an inflated out_len, sidsbuf_end will point past the\nend of the iov. This defeats the bounds guards in posix_info_sid_size(),\nallowing out-of-bounds reads into adjacent kernel memory.\n\nFix this by rejecting responses where the calculated sidsbuf_end would\nexceed the received iov boundaries or cause pointer wraparound." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H", "baseScore": 8.1, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:N - A malicious SMB server supplies the malformed OutputBufferLength and SID payload in an SMB2 QUERY_INFO response over TCP; cifs_root_iget() or cifs_getattr() reaches smb2_query_path_info(), smb2_compound_op(), then parse_posix_sids().\nAC:L - The server can place a valid SID header at the iov boundary and set num_subauth so parse_posix_sids() copies up to 68 bytes beyond it. Once the POSIX mount exists, triggering is deterministic and requires no race or uncontrollable heap state.\nPR:N - Session setup and tree connect precede compound_send_recv(), but the attacker is the SMB server endpoint and needs no account or capability on the client to choose the QUERY_INFO response.\nUI:R - The victim must mount the attacker-controlled share with the posix option, which sets ctx->linux_ext; cifs_read_super() then calls cifs_root_iget(), which immediately issues the vulnerable POSIX metadata query.\nS:U - The out-of-bounds access occurs in the SMB client and affects the same host kernel executing parse_posix_sids(); it crosses no VM, IOMMU, or sandbox security boundary.\nC:H - An inflated end pointer defeats posix_info_sid_size() bounds checks, allowing each owner or group SID memcpy() to consume up to 68 bytes of adjacent kernel memory and pass those bytes into SID/idmap processing.\nI:N - posix_info_sid_size() caps num_subauth at 15, so each memcpy() remains within its destination struct smb_sid; the defect performs out-of-bounds reads but provides no out-of-bounds write or control-flow modification.\nA:H - By ending the received iov at a SID header while claiming a larger OutputBufferLength, the server makes posix_info_sid_size() and memcpy() access beyond the receive allocation, which can fault and oops or panic the client kernel." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/smb/client/smb2inode.c" ], "versions": [ { "version": "a90f37e3d7acfd9824f162830583bbf7846fe252", "lessThan": "d91b9a3b2b38e5ac1b51e9e5b23fe53ad7b49644", "status": "affected", "versionType": "git" }, { "version": "858e74876c5cbff1dfd5bace99e32fbce2abd4b5", "lessThan": "b862996e5105be1293da9cdc85da77b76021c3bd", "status": "affected", "versionType": "git" }, { "version": "858e74876c5cbff1dfd5bace99e32fbce2abd4b5", "lessThan": "2f8ed71aaaba3bc8b19cd9930cc62e63e142b299", "status": "affected", "versionType": "git" }, { "version": "858e74876c5cbff1dfd5bace99e32fbce2abd4b5", "lessThan": "eac6917a42899aad0617bbf04798c5dd946a1fe5", "status": "affected", "versionType": "git" }, { "version": "858e74876c5cbff1dfd5bace99e32fbce2abd4b5", "lessThan": "b09d092eb24ad0110f16a9b7c1ed5d2a0c1733dc", "status": "affected", "versionType": "git" }, { "version": "6.6.32", "lessThan": "6.6.158", "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/client/smb2inode.c" ], "versions": [ { "version": "6.8", "status": "affected" }, { "version": "0", "lessThan": "6.8", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.158", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.112", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.54", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.8", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.3", "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": "6.6.32", "versionEndExcluding": "6.6.158" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.8", "versionEndExcluding": "6.12.112" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.8", "versionEndExcluding": "6.18.54" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.8", "versionEndExcluding": "7.2.8" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.8", "versionEndExcluding": "7.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/d91b9a3b2b38e5ac1b51e9e5b23fe53ad7b49644" }, { "url": "https://git.kernel.org/stable/c/b862996e5105be1293da9cdc85da77b76021c3bd" }, { "url": "https://git.kernel.org/stable/c/2f8ed71aaaba3bc8b19cd9930cc62e63e142b299" }, { "url": "https://git.kernel.org/stable/c/eac6917a42899aad0617bbf04798c5dd946a1fe5" }, { "url": "https://git.kernel.org/stable/c/b09d092eb24ad0110f16a9b7c1ed5d2a0c1733dc" } ], "title": "smb: client: fix missing iov bounds check in parse_posix_sids()", "x_generator": { "engine": "bippy-1.2.0" } } } }