smb: client: fix OOB read in smb2_ioctl_query_info QUERY_INFO path

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Summary

CVECVE-2026-31708
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-05-01 14:16:20 UTC
Updated2026-05-03 07:16:18 UTC
DescriptionIn 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.

Risk And Classification

Primary CVSS: v3.1 8.1 HIGH from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H

EPSS: 0.000180000 probability, percentile 0.048520000 (date 2026-05-02)

VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary8.1HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H
3.1CNADECLARED8.1HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected f5778c398713692a16150ae96e5c8270bab8399f a34d456934fe42e4da5d2cc07787bf418bee99c6 git Not specified
CNA Linux Linux affected f5778c398713692a16150ae96e5c8270bab8399f ac2f14e4705d020f04e806efa0d49ab8dc2b145f git Not specified
CNA Linux Linux affected f5778c398713692a16150ae96e5c8270bab8399f 078fae8f50adebb903ccf2252b44391324571e78 git Not specified
CNA Linux Linux affected f5778c398713692a16150ae96e5c8270bab8399f 85fd46ee26a11841c670449508025965f61ce131 git Not specified
CNA Linux Linux affected f5778c398713692a16150ae96e5c8270bab8399f a58c5af19ff0d6f44f6e9fe31e33a2c92223f77e git Not specified
CNA Linux Linux affected 5.1 Not specified
CNA Linux Linux unaffected 5.1 semver Not specified
CNA Linux Linux unaffected 6.6.136 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.84 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.25 6.18.* semver Not specified
CNA Linux Linux unaffected 7.0.2 7.0.* semver Not specified
CNA Linux Linux unaffected 7.1-rc1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/ac2f14e4705d020f04e806efa0d49ab8dc2b145f 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/85fd46ee26a11841c670449508025965f61ce131 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/078fae8f50adebb903ccf2252b44391324571e78 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/a34d456934fe42e4da5d2cc07787bf418bee99c6 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/a58c5af19ff0d6f44f6e9fe31e33a2c92223f77e 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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