Cyber Resilience

CVE-2025-21944

Linux Kernel 5.15 – 6.1.131

Published
01 April 2025
Modified
03 November 2025
Patch / advisory
View advisory
CVSS Score v3.1 5.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS Score 0.0015 4th percentile
Risk Priority 41 floored blend · peak EPSS

Summary

CVE-2025-21944 is a medium-severity Improper Locking (CWE-667) vulnerability in Linux Linux Kernel. Its CVSS base score is 5.5 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Endpoint Denial of Service (T1499); ranked at the 4th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability Data

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix bug on trap in smb2_lock If lock count is greater than 1, flags could be old value. It should be checked with flags of smb_lock, not flags. It…

more

will cause bug-on trap from locks_free_lock in error handling routine.

CWE(s)
CWE-667

Related Threats

MITRE ATT&CK Enterprise Techniques

T1499 Endpoint Denial of Service Impact
Adversaries may perform Endpoint Denial of Service (DoS) attacks to degrade or block the availability of services to users.
attack.mitre.org →
T1499.004 Application or System Exploitation Impact
Adversaries may exploit software vulnerabilities that can cause an application or system to crash and deny availability to users.
attack.mitre.org →
T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
attack.mitre.org →
T1548 Abuse Elevation Control Mechanism Privilege Escalation
Adversaries may circumvent mechanisms designed to control privilege elevation to gain higher-level permissions.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

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CVE-2024-56743Same product: Linux Linux Kernel
CVE-2024-35997Same product: Linux Linux Kernel
CVE-2026-45924Same product: Linux Linux Kernel
CVE-2023-53031Same product: Linux Linux Kernel
CVE-2024-57903Same product: Linux Linux Kernel
CVE-2024-40972Same product: Linux Linux Kernel
CVE-2024-35999Same product: Linux Linux Kernel
CVE-2025-21767Same product: Linux Linux Kernel

Affected Assets

linux
linux kernel
6.14 · 5.15 — 6.1.131 · 6.2 — 6.6.83 · 6.7 — 6.12.19

Mitigating Controls

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly include code reviews, static analysis, and concurrency standards that prevent improper locking.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.29 Security testing in development and acceptance mostly match
finds

Security testing can detect race conditions and locking errors before release.

A.8.25 Secure development life cycle partial match
prevents

Secure development lifecycle includes concurrency and locking requirements that reduce improper locking defects.

A.8.26 Application security requirements partial match
prevents

Application security requirements can mandate proper lock acquisition/release patterns.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure architecture principles address thread-safety and resource synchronization.

A.8.28 Secure coding partial match
prevents

Secure coding standards directly prohibit missing or incorrect lock usage.

A.8.32 Change management partial match
prevents

Change management may catch locking issues introduced by modifications but does not prevent the weakness itself.

References