Cyber Resilience

CVE-2025-21962

Memory Safety in Linux Kernel 5.15.107 – 5.15.180

Published
01 April 2025
Modified
03 November 2025
Patch / 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 0.0018 8th percentile
Risk Priority 35 floored blend · peak EPSS

Summary

CVE-2025-21962 is a medium-severity Integer Overflow or Wraparound (CWE-190) vulnerability in Linux Linux Kernel. Its CVSS base score is 5.5 (Medium).

Operationally, ranked at the 8th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SI-10 (Information Input Validation) and SA-11 (Developer Testing and Evaluation) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

In the Linux kernel, the following vulnerability has been resolved: cifs: Fix integer overflow while processing closetimeo mount option User-provided mount parameter closetimeo of type u32 is intended to have an upper limit, but before it is validated, the value…

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is converted from seconds to jiffies which can lead to an integer overflow. Found by Linux Verification Center (linuxtesting.org) with SVACE.

CWE(s)

Related Threats

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CVE-2025-21711Same product: Linux Linux Kernel

Affected Assets

linux
linux kernel
6.14 · 5.15.107 — 5.15.180 · 6.0 — 6.1.132 · 6.2 — 6.6.84

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)
  • SI-10 Information Input Validation
  • SA-11 Developer Testing and Evaluation
Detect
Catch it (NIST detect / respond)
  • SI-2 Flaw Remediation
Harden
Shrink the surface (DISA STIG)

Validate
Prove the fix (OWASP ASVS)
  • V5.2.6

Mitigating Controls (NIST 800-53 r5) AI

prevent

Directly enforces validation of the untrusted u32 closetimeo mount parameter before any arithmetic conversion to jiffies, preventing the integer overflow.

prevent

Requires developer testing and static analysis capable of detecting integer-overflow conditions during conversion of user-supplied time values.

respondrecover

Mandates prompt application of the kernel patch that moves validation before the seconds-to-jiffies conversion.

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 require use of safe arithmetic, bounds checks, and testing that prevent integer overflows.

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.

detects

Security testing in development can detect integer overflows before release.

prevents

Secure SDLC mandates input validation and arithmetic checks that prevent integer overflows.

degrades

Application security requirements include bounds checking and safe arithmetic to avoid overflow conditions.

degrades

Secure architecture principles require defensive coding patterns that mitigate integer wraparound risks.

prevents

Secure coding standards explicitly forbid unsafe integer operations and mandate overflow-safe constructs.

References