ksmbd: use memcmp() to compare ClientGUIDs

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-74521
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-15 13:17:57 UTC
Updated2026-08-17 06:19:48 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: ksmbd: use memcmp() to compare ClientGUIDs ClientGUID is a fixed-size binary value and can contain embedded NUL bytes. strncmp() stops comparing at the first NUL byte, so different ClientGUID values can incorrectly be treated as equal. Use memcmp() in SMB3 multichannel session binding and FSCTL_VALIDATE_NEGOTIATE_INFO to compare all SMB2_CLIENT_GUID_SIZE bytes.

Risk And Classification

Primary CVSS: v3.1 9.1 CRITICAL from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

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

EPSS: 0.001550000 probability, percentile 0.051990000 (date 2026-08-16)

VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary9.1CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
3.1CNADECLARED9.1CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

CVSS v3.1 Breakdown

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

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 d535363299822c5caa543787b21bd5cfa3e41949 git Not specified
CNA Linux Linux affected e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 e8bb506e6ef749ac0336f3e579d8d02396b7d832 git Not specified
CNA Linux Linux affected 5.15 Not specified
CNA Linux Linux unaffected 5.15 semver Not specified
CNA Linux Linux unaffected 7.1.8 7.1.* semver Not specified
CNA Linux Linux unaffected 7.2 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/d535363299822c5caa543787b21bd5cfa3e41949 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/e8bb506e6ef749ac0336f3e579d8d02396b7d832 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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