{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-31708", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-03-09T15:48:24.132Z", "datePublished": "2026-05-01T13:56:05.880Z", "dateUpdated": "2026-08-05T12:24:43.143Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:24:43.143Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix OOB read in smb2_ioctl_query_info QUERY_INFO path\n\nsmb2_ioctl_query_info() has two response-copy branches: PASSTHRU_FSCTL\nand the default QUERY_INFO path. The QUERY_INFO branch clamps\nqi.input_buffer_length to the server-reported OutputBufferLength and then\ncopies qi.input_buffer_length bytes from qi_rsp->Buffer to userspace, but\nit never verifies that the flexible-array payload actually fits within\nrsp_iov[1].iov_len.\n\nA malicious server can return OutputBufferLength larger than the actual\nQUERY_INFO response, causing copy_to_user() to walk past the response\nbuffer and expose adjacent kernel heap to userspace.\n\nGuard the QUERY_INFO copy with a bounds check on the actual Buffer\npayload. Use struct_size(qi_rsp, Buffer, qi.input_buffer_length)\nrather than an open-coded addition so the guard cannot overflow on\n32-bit builds." } ], "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 - The attacker-controlled data is an SMB2 QUERY_INFO response sent by a remote SMB server to the kernel SMB client over the network. The vulnerable copy is reached after the client issues the ioctl-triggered compound open/query/close request.\nAC:L - There is no race or fragile timing requirement; a malicious server controls the malformed response fields and can reliably make the advertised copy length exceed the actual response payload. CIFS/SMB client support is common and the affected SMB2+ path is not a rare configuration.\nPR:N - The malicious SMB server needs no privileges on the vulnerable client. The affected PASSTHRU_QUERY_INFO branch has no CAP_SYS_ADMIN check, unlike the FSCTL and SET_INFO branches.\nUI:R - A victim or local process must have mounted/accessed the SMB share and issued the CIFS_QUERY_INFO ioctl. The malicious server cannot reach this ioctl path entirely unsolicited.\nS:U - The impact is within the vulnerable kernel/client system security scope. This is not a VM escape, IOMMU bypass, or cross-authority boundary violation.\nC:H - The bug is an out-of-bounds kernel read copied to userspace from beyond the received SMB response buffer. The overread can expose adjacent kernel heap data and is not strictly bounded to only a few harmless bytes.\nI:N - The vulnerable operation is a read from kernel memory followed by copy_to_user. It does not provide a kernel write primitive or direct data modification.\nA:H - The same attacker-controlled length can drive copy_to_user far beyond the valid response buffer. That can trigger kernel faults or hardened usercopy failures, so a kernel crash is a defensible impact." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/smb/client/smb2ops.c" ], "versions": [ { "version": "f5778c398713692a16150ae96e5c8270bab8399f", "lessThan": "e66bdc0704977ecee667a81d38255b579c2353d0", "status": "affected", "versionType": "git" }, { "version": "f5778c398713692a16150ae96e5c8270bab8399f", "lessThan": "9e203dbb5402897c43130fb171a2617008a91f45", "status": "affected", "versionType": "git" }, { "version": "f5778c398713692a16150ae96e5c8270bab8399f", "lessThan": "1dd757379997b71a328a4b591ffaf481acd0ead1", "status": "affected", "versionType": "git" }, { "version": "f5778c398713692a16150ae96e5c8270bab8399f", "lessThan": "a34d456934fe42e4da5d2cc07787bf418bee99c6", "status": "affected", "versionType": "git" }, { "version": "f5778c398713692a16150ae96e5c8270bab8399f", "lessThan": "ac2f14e4705d020f04e806efa0d49ab8dc2b145f", "status": "affected", "versionType": "git" }, { "version": "f5778c398713692a16150ae96e5c8270bab8399f", "lessThan": "078fae8f50adebb903ccf2252b44391324571e78", "status": "affected", "versionType": "git" }, { "version": "f5778c398713692a16150ae96e5c8270bab8399f", "lessThan": "85fd46ee26a11841c670449508025965f61ce131", "status": "affected", "versionType": "git" }, { "version": "f5778c398713692a16150ae96e5c8270bab8399f", "lessThan": "a58c5af19ff0d6f44f6e9fe31e33a2c92223f77e", "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/client/smb2ops.c" ], "versions": [ { "version": "5.1", "status": "affected" }, { "version": "0", "lessThan": "5.1", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.259", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.210", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.175", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.136", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.84", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.25", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.0.2", "lessThanOrEqual": "7.0.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1", "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": "5.1", "versionEndExcluding": "5.10.259" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.1", "versionEndExcluding": "5.15.210" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.1", "versionEndExcluding": "6.1.175" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.1", "versionEndExcluding": "6.6.136" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.1", "versionEndExcluding": "6.12.84" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.1", "versionEndExcluding": "6.18.25" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.1", "versionEndExcluding": "7.0.2" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.1", "versionEndExcluding": "7.1" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/e66bdc0704977ecee667a81d38255b579c2353d0" }, { "url": "https://git.kernel.org/stable/c/9e203dbb5402897c43130fb171a2617008a91f45" }, { "url": "https://git.kernel.org/stable/c/1dd757379997b71a328a4b591ffaf481acd0ead1" }, { "url": "https://git.kernel.org/stable/c/a34d456934fe42e4da5d2cc07787bf418bee99c6" }, { "url": "https://git.kernel.org/stable/c/ac2f14e4705d020f04e806efa0d49ab8dc2b145f" }, { "url": "https://git.kernel.org/stable/c/078fae8f50adebb903ccf2252b44391324571e78" }, { "url": "https://git.kernel.org/stable/c/85fd46ee26a11841c670449508025965f61ce131" }, { "url": "https://git.kernel.org/stable/c/a58c5af19ff0d6f44f6e9fe31e33a2c92223f77e" } ], "title": "smb: client: fix OOB read in smb2_ioctl_query_info QUERY_INFO path", "x_generator": { "engine": "bippy-1.2.0" } } } }