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CVE-2026-31574 Linux CVE debrief

A vulnerability in the Linux kernel's clock events subsystem could cause system stalls due to timer interrupt starvation. The issue stems from the `next_event_forced` flag not being reset in three specific scenarios: when the clock event state changes (potentially leaving the flag stale across shutdown/startup sequences), when a non-forced event is armed (preventing rearming and causing missed interrupts if the event is far in the future), and in the suspend wakeup handler. The vulnerability affects Linux kernel 7.0 and has been resolved by adding the missing flag resets. The CVSS 3.1 score of 5.5 (MEDIUM) reflects local attack vector with low attack complexity and low privileges required, resulting in high availability impact. No known exploitation in the wild has been reported, and this vulnerability is not listed in CISA's Known Exploited Vulnerabilities catalog.

Vendor
Linux
Product
Unknown
CVSS
MEDIUM 5.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-04-24
Original CVE updated
2026-05-19
Advisory published
2026-04-24
Advisory updated
2026-05-19

Who should care

System administrators and security teams managing Linux kernel 7.0 deployments, particularly those with workloads sensitive to timer latency or systems experiencing unexplained stalls during suspend/resume operations

Technical summary

The Linux kernel's clock events subsystem contains a logic error where the `next_event_forced` flag is not properly reset in three code paths: clock event state transitions, non-forced event arming, and the suspend wakeup handler. This can lead to stale flag state that prevents proper timer rearming, resulting in missed timer interrupts and system stalls. The vulnerability is local-only with no confidentiality or integrity impact, but can cause denial of service through availability degradation.

Defensive priority

medium

Recommended defensive actions

  • Apply the relevant kernel patches from the stable kernel tree to address the missing `next_event_forced` flag resets
  • Monitor system logs for timer-related stalls or interrupt starvation symptoms, particularly after suspend/resume cycles or clock event state changes
  • Consider upgrading to a patched kernel version when available through distribution channels
  • Review systems running Linux kernel 7.0 for exposure to this vulnerability

Evidence notes

Vulnerability description and patch references sourced from NVD. Affected product identified as Linux kernel 7.0 via CPE criteria. CVSS vector confirms local attack vector with availability impact. Two kernel.org patches provided as mitigation references.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-31574 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-31574

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-31574 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-31574

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

  • Mitigation or vendor reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/4096fd0e8eaea13ebe5206700b33f49635ae18e5

    416baaa9-dc9f-4396-8d5f-8c081fb06d67 - Patch

  • Mitigation or vendor reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/9401b593fa48218d2667df1610b0ebc518554880

    416baaa9-dc9f-4396-8d5f-8c081fb06d67 - Patch

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.