CVE-2026-74521

Linux kernel vulnerability

9.1 CRITICALEPSS 0.41%

Published15 Aug 2026

Description

In 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.

CVSS 3.1 breakdown

Attack vectorNetwork

Attack complexityLow

Privileges requiredNone

User interactionNone

ScopeUnchanged

ConfidentialityHigh

IntegrityHigh

AvailabilityNone

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

Remediation

No fixed version is recorded in the NVD data. Check the vendor advisory for the latest guidance.

References

Frequently asked

Is CVE-2026-74521 being actively exploited?

CVE-2026-74521 is not in the CISA KEV catalog. Its EPSS exploit probability is 0.41%.

How severe is CVE-2026-74521?

CVE-2026-74521 has a CVSS 3.1 base score of 9.1, rated critical. EPSS estimates a 0.41% probability of exploitation.

How do I fix CVE-2026-74521?

Apply the vendor's patch or advisory guidance, then verify no affected versions remain across your devices.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-74521 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.