CVE-2026-31708

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix OOB read in smb2_ioctl_query_info QUERY_INFO path smb2_ioctl_query_info() has two response-copy branches: PASSTHRU_FSCTL and the default QUERY_INFO path. The QUERY_INFO branch clamps qi.input_buffer_length to the server-reported OutputBufferLength and then copies qi.input_buffer_length bytes from qi_rsp->Buffer to userspace, but it never verifies that the flexible-array payload actually fits within rsp_iov[1].iov_len. A malicious server can return OutputBufferLength larger than the actual QUERY_INFO response, causing copy_to_user() to walk past the response buffer and expose adjacent kernel heap to userspace. Guard the QUERY_INFO copy with a bounds check on the actual Buffer payload. Use struct_size(qi_rsp, Buffer, qi.input_buffer_length) rather than an open-coded addition so the guard cannot overflow on 32-bit builds.

CVSS v3 8.1 HIGH

8.1^/10

CVSS v3 : HIGH

Vector :

Exploitability : 2.8 / Impact : 5.2

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction REQUIRED

Confidentiality Impact HIGH

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://git.kernel.org/stable/c/078fae8f50adebb903ccf2252b44391324571e78	Patch
https://git.kernel.org/stable/c/1dd757379997b71a328a4b591ffaf481acd0ead1
https://git.kernel.org/stable/c/85fd46ee26a11841c670449508025965f61ce131	Patch
https://git.kernel.org/stable/c/9e203dbb5402897c43130fb171a2617008a91f45
https://git.kernel.org/stable/c/a34d456934fe42e4da5d2cc07787bf418bee99c6	Patch
https://git.kernel.org/stable/c/a58c5af19ff0d6f44f6e9fe31e33a2c92223f77e	Patch
https://git.kernel.org/stable/c/ac2f14e4705d020f04e806efa0d49ab8dc2b145f	Patch
https://git.kernel.org/stable/c/e66bdc0704977ecee667a81d38255b579c2353d0

Configurations

Configuration 1 (hide)

OR	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::

History

No history.

Information

Published : 2026-05-01 14:16

Updated : 2026-06-19 13:16

NVD link : CVE-2026-31708

Mitre link : CVE-2026-31708

CVE.ORG link : CVE-2026-31708

JSON object : View

Products Affected

linux

linux_kernel

CWE

CWE-125

Out-of-bounds Read

{"id": "CVE-2026-31708", "cveTags": [], "metrics": {"cvssMetricV31": [{"type": "Secondary", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 8.1, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "REQUIRED", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "HIGH"}, "impactScore": 5.2, "exploitabilityScore": 2.8}]}, "affected": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "affectedData": [{"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "f5778c398713692a16150ae96e5c8270bab8399f", "lessThan": "e66bdc0704977ecee667a81d38255b579c2353d0", "versionType": "git"}, {"status": "affected", "version": "f5778c398713692a16150ae96e5c8270bab8399f", "lessThan": "9e203dbb5402897c43130fb171a2617008a91f45", "versionType": "git"}, {"status": "affected", "version": "f5778c398713692a16150ae96e5c8270bab8399f", "lessThan": "1dd757379997b71a328a4b591ffaf481acd0ead1", "versionType": "git"}, {"status": "affected", "version": "f5778c398713692a16150ae96e5c8270bab8399f", "lessThan": "a34d456934fe42e4da5d2cc07787bf418bee99c6", "versionType": "git"}, {"status": "affected", "version": "f5778c398713692a16150ae96e5c8270bab8399f", "lessThan": "ac2f14e4705d020f04e806efa0d49ab8dc2b145f", "versionType": "git"}, {"status": "affected", "version": "f5778c398713692a16150ae96e5c8270bab8399f", "lessThan": "078fae8f50adebb903ccf2252b44391324571e78", "versionType": "git"}, {"status": "affected", "version": "f5778c398713692a16150ae96e5c8270bab8399f", "lessThan": "85fd46ee26a11841c670449508025965f61ce131", "versionType": "git"}, {"status": "affected", "version": "f5778c398713692a16150ae96e5c8270bab8399f", "lessThan": "a58c5af19ff0d6f44f6e9fe31e33a2c92223f77e", "versionType": "git"}], "programFiles": ["fs/smb/client/smb2ops.c"], "defaultStatus": "unaffected"}, {"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "5.1"}, {"status": "unaffected", "version": "0", "lessThan": "5.1", "versionType": "semver"}, {"status": "unaffected", "version": "5.10.259", "versionType": "semver", "lessThanOrEqual": "5.10.*"}, {"status": "unaffected", "version": "5.15.210", "versionType": "semver", "lessThanOrEqual": "5.15.*"}, {"status": "unaffected", "version": "6.1.175", "versionType": "semver", "lessThanOrEqual": "6.1.*"}, {"status": "unaffected", "version": "6.6.136", "versionType": "semver", "lessThanOrEqual": "6.6.*"}, {"status": "unaffected", "version": "6.12.84", "versionType": "semver", "lessThanOrEqual": "6.12.*"}, {"status": "unaffected", "version": "6.18.25", "versionType": "semver", "lessThanOrEqual": "6.18.*"}, {"status": "unaffected", "version": "7.0.2", "versionType": "semver", "lessThanOrEqual": "7.0.*"}, {"status": "unaffected", "version": "7.1", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*"}], "programFiles": ["fs/smb/client/smb2ops.c"], "defaultStatus": "affected"}]}], "published": "2026-05-01T14:16:20.837", "references": [{"url": "https://git.kernel.org/stable/c/078fae8f50adebb903ccf2252b44391324571e78", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/1dd757379997b71a328a4b591ffaf481acd0ead1", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/85fd46ee26a11841c670449508025965f61ce131", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/9e203dbb5402897c43130fb171a2617008a91f45", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/a34d456934fe42e4da5d2cc07787bf418bee99c6", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/a58c5af19ff0d6f44f6e9fe31e33a2c92223f77e", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/ac2f14e4705d020f04e806efa0d49ab8dc2b145f", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/e66bdc0704977ecee667a81d38255b579c2353d0", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "vulnStatus": "Modified", "weaknesses": [{"type": "Primary", "source": "nvd@nist.gov", "description": [{"lang": "en", "value": "CWE-125"}]}], "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."}], "lastModified": "2026-06-19T13:16:27.003", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "B28CAC2A-4B06-4D07-8736-82E515099010", "versionEndExcluding": "6.6.136", "versionStartIncluding": "5.1"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "D4ECA0DE-AFF5-4688-B219-4CA2336CA5B7", "versionEndExcluding": "6.12.84", "versionStartIncluding": "6.7"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "8B0A7E0E-F6D8-45DB-8CD9-01839FE40A6C", "versionEndExcluding": "6.18.25", "versionStartIncluding": "6.13"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "1BD58F1E-7C20-4C0D-92A2-FAC5CBFBE8A8", "versionEndExcluding": "7.0.2", "versionStartIncluding": "6.19"}], "operator": "OR"}]}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}