Cyber Resilience

CVE-2025-39727

Memory Safety in Linux Kernel 6.12 – 6.12.42

Published
07 September 2025
Modified
25 November 2025
Patch / advisory
CVSS Score v3.1 7.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0016 6th percentile
Risk Priority 55 floored blend · peak EPSS

Summary

CVE-2025-39727 is a high-severity Classic Buffer Overflow (CWE-120) vulnerability in Linux Linux Kernel. Its CVSS base score is 7.8 (High).

Operationally, ranked at the 6th 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 SI-16 (Memory Protection) — 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: mm: swap: fix potential buffer overflow in setup_clusters() In setup_swap_map(), we only ensure badpages are in range (0, last_page]. As maxpages might be < last_page, setup_clusters() will encounter a buffer…

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overflow when a badpage is >= maxpages. Only call inc_cluster_info_page() for badpage which is < maxpages to fix the issue.

CWE(s)

Related Threats

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Affected Assets

linux
linux kernel
6.12 — 6.12.42 · 6.13 — 6.15.10 · 6.16 — 6.16.1

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)
  • SI-10 Information Input Validation
  • SI-16 Memory Protection
  • SI-2 Flaw Remediation
Detect
Catch it (NIST detect / respond)
  • SI-2 Flaw Remediation
Harden
Shrink the surface (DISA STIG)

Validate
Prove the fix (OWASP ASVS)
  • V5.2.1

Mitigating Controls (NIST 800-53 r5) AI

prevent

Directly requires validation of all input parameters (badpage vs. maxpages) before use in setup_clusters(), eliminating the unchecked buffer access.

prevent

Enforces memory bounds checking and protection mechanisms that would block or contain the overflow when a badpage >= maxpages is processed.

preventrecover

Mandates timely application of the kernel patch that adds the missing maxpages check in setup_swap_map() and setup_clusters().

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 development practices directly enforce bounds checking and input validation that prevent classic buffer overflows.

ID.RA-01 partial match
prevents

Vulnerability identification processes such as code review or scanning detect classic buffer overflows before exploitation.

PR.PS-02 partial match
prevents

Routine patching replaces vulnerable code containing unchecked buffer copies with corrected versions.

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.

prevents

Secure coding directly requires bounds-checked memory operations, addressing the root cause of CWE-120.

detects

Security testing in development and acceptance can detect buffer overflows through fuzzing and static analysis, though it does not prevent them at the source.

prevents

Secure development life cycle mandates processes that can include input validation and bounds checking to prevent buffer overflows.

prevents

Application security requirements can specify input-size validation and safe buffer handling to mitigate classic buffer overflows.

prevents

Secure system architecture and engineering principles promote defensive coding patterns that reduce the likelihood of unchecked buffer copies.

References