Cyber Resilience

CVE-2026-31642

DoS in Linux Kernel 4.13.1 – 6.6.135

Published
24 April 2026
Modified
01 June 2026
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 0.0012 2th percentile
Risk Priority 35 floored blend · peak EPSS

Summary

CVE-2026-31642 is a medium-severity Infinite Loop (CWE-835) vulnerability in Linux Linux Kernel. Its CVSS base score is 5.5 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Application or System Exploitation (T1499.004); ranked at the 2th 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-11 (Developer Testing and Evaluation) and SI-4 (System Monitoring) — 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: rxrpc: Fix call removal to use RCU safe deletion Fix rxrpc call removal from the rxnet->calls list to use list_del_rcu() rather than list_del_init() to prevent stuffing up reading /proc/net/rxrpc/calls from…

more

potentially getting into an infinite loop. This, however, means that list_empty() no longer works on an entry that's been deleted from the list, making it harder to detect prior deletion. Fix this by: Firstly, make rxrpc_destroy_all_calls() only dump the first ten calls that are unexpectedly still on the list. Limiting the number of steps means there's no need to call cond_resched() or to remove calls from the list here, thereby eliminating the need for rxrpc_put_call() to check for that. rxrpc_put_call() can then be fixed to unconditionally delete the call from the list as it is the only place that the deletion occurs.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

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.
Why these techniques?

Kernel bug (CWE-835 infinite loop in proc read path) directly enables local DoS via system exploitation.

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

CVEs Like This One

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CVE-2026-23109Same product: Linux Linux Kernel
CVE-2026-31498Same product: Linux Linux Kernel
CVE-2026-23082Same product: Linux Linux Kernel
CVE-2026-43096Same product: Linux Linux Kernel
CVE-2026-43486Same product: Linux Linux Kernel
CVE-2026-46314Same product: Linux Linux Kernel

Affected Assets

linux
linux kernel
4.13, 7.0 · 4.13.1 — 6.6.135 · 6.7 — 6.12.82 · 6.13 — 6.18.23

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)
  • SA-11 Developer Testing and Evaluation
  • SI-7 Software, Firmware, and Information Integrity
Detect
Catch it (NIST detect / respond)
  • SI-7 Software, Firmware, and Information Integrity
  • SI-4 System Monitoring
Harden
Shrink the surface (DISA STIG)

Validate
Prove the fix (OWASP ASVS)

Mitigating Controls (NIST 800-53 r5) AI

prevent

Developer testing and evaluation of list/RCU operations and /proc readers would have detected the non-RCU deletion that enables the infinite loop.

preventdetect

Verifying software integrity after kernel builds or module loads can block or detect introduction of the flawed rxrpc call-list handling.

detect

Continuous system monitoring of CPU and procfs activity would identify the runaway loop when /proc/net/rxrpc/calls is read after a call is removed.

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 (reviews, testing, static analysis) directly prevent introduction of infinite-loop defects.

ID.RA-01 partial match
prevents

Static analysis and vuln scanning during asset assessment can detect unreachable loop exits.

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 can uncover infinite-loop conditions before release.

prevents

Secure development life cycle mandates practices that can detect and prevent infinite-loop defects.

prevents

Application security requirements can specify loop-termination rules, indirectly reducing the weakness.

prevents

Secure coding standards directly address loop termination and prevent infinite loops.

none

Secure architecture principles encourage designs that avoid unreachable exit conditions.

none

Change management can require review of loop logic when code is modified.

References