Cyber Resilience

CVE-2025-39826

Memory Safety in Linux Kernel 2.6.12.1 – 6.1.150

Published
16 September 2025
Modified
14 July 2026
Patch / advisory
CVSS Score v3.1 7.0
Click a component to see what it means
Raw vectorCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0013 3th percentile
Risk Priority 55 floored blend · peak EPSS

Summary

CVE-2025-39826 is a high-severity Use After Free (CWE-416) vulnerability in Linux Linux Kernel. Its CVSS base score is 7.0 (High).

Operationally, ranked at the 3th 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 SA-8 (Security and Privacy Engineering Principles) 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: net: rose: convert 'use' field to refcount_t The 'use' field in struct rose_neigh is used as a reference counter but lacks atomicity. This can lead to race conditions where a…

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rose_neigh structure is freed while still being referenced by other code paths. For example, when rose_neigh->use becomes zero during an ioctl operation via rose_rt_ioctl(), the structure may be removed while its timer is still active, potentially causing use-after-free issues. This patch changes the type of 'use' from unsigned short to refcount_t and updates all code paths to use rose_neigh_hold() and rose_neigh_put() which operate reference counts atomically.

CWE(s)

Related Threats

CVEs Like This One

CVE-2025-38578Same product: Debian Debian Linux
CVE-2025-37885Same product: Debian Debian Linux
CVE-2024-26689Same product: Debian Debian Linux
CVE-2024-35867Same product: Debian Debian Linux
CVE-2025-39689Same product: Debian Debian Linux
CVE-2024-42314Same product: Debian Debian Linux
CVE-2025-39877Same product: Debian Debian Linux
CVE-2024-26598Same product: Debian Debian Linux
CVE-2023-52572Same product: Debian Debian Linux
CVE-2025-38476Same product: Debian Debian Linux

Affected Assets

linux
linux kernel
2.6.12, 6.17 · 2.6.12.1 — 6.1.150 · 6.2 — 6.6.104 · 6.7 — 6.12.45
debian
debian linux
11.0

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)
  • SA-8 Security and Privacy Engineering Principles
  • SA-11 Developer Testing and Evaluation
  • SI-16 Memory Protection
Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)
  • 3 hardening rules · 3 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V1.4.3

Mitigating Controls (NIST 800-53 r5) AI

prevent

Requires application of secure engineering principles (atomic reference counting, safe object lifetime management) that directly eliminate the non-atomic 'use' counter race leading to UAF in rose_neigh.

prevent

Mandates developer security testing and evaluation (including concurrency and reference-count stress testing) that would detect the race condition before the flawed rose_neigh implementation ships.

prevent

Employs memory-protection safeguards that can reduce exploitability of the resulting use-after-free once the reference-count bug is triggered.

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 incorporate memory-safety tooling and reviews that prevent most use-after-free defects.

ID.RA-01 partial match
prevents

Vulnerability identification processes can discover use-after-free issues via scanning or analysis but do not prevent their introduction.

PR.PS-02 partial match
prevents

Routine patching removes known use-after-free instances after they have been introduced in released software.

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 use-after-free bugs before release.

prevents

Secure SDLC mandates memory-safety practices that reduce use-after-free defects.

prevents

Application security requirements can specify memory-management rules that mitigate use-after-free.

prevents

Secure architecture principles include memory-safety design choices that limit use-after-free exposure.

prevents

Secure coding standards directly prescribe avoidance of use-after-free patterns.

prevents

Change-management processes help ensure memory-safety fixes are deployed consistently.

References