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CVE-2026-64425 Linux CVE debrief

A vulnerability in the Linux kernel's io_uring/io-wq subsystem has been addressed. The issue involves re-checking the IO_WQ_BIT_EXIT bit for each linked work item to prevent use-after-free and potential crashes. This CVE has a CVSS score of 5.5 and is considered MEDIUM severity. The vulnerability was introduced due to a missing re-check of the IO_WQ_BIT_EXIT bit in the io_worker_handle_work() function, which could lead to use-after-free and potential crashes. The fix involves moving the check further inside the work run loop to cover linked items too.

Vendor
Linux
Product
Unknown
CVSS
MEDIUM 5.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-07-25
Original CVE updated
2026-10-15
Advisory published
2026-07-25
Advisory updated
2026-10-15

Who should care

Linux system administrators, security teams, and developers responsible for maintaining and securing Linux-based systems should be aware of this vulnerability and take necessary actions to mitigate potential risks.

Why it matters

This vulnerability in the Linux kernel's io_uring/io-wq subsystem requires attention from Linux system administrators and security teams to assess exposure and apply necessary patches or mitigations.

  • Verify Linux system exposure to this vulnerability
  • Apply patches or mitigations to prevent potential crashes
  • Monitor system logs for exploitation attempts

Technical summary

The Linux kernel's io_uring/io-wq subsystem has a vulnerability that requires re-checking the IO_WQ_BIT_EXIT bit for each linked work item. This issue can lead to use-after-free and potential crashes. The vulnerability has been addressed through a series of commits. The fix involves moving the check further inside the work run loop to cover linked items too. The vulnerability has a CVSS score of 5.5 and is considered MEDIUM severity. Linux system administrators and security teams should assess exposure and apply patches or mitigations as needed.

Defensive priority

Linux system administrators and security teams should assess exposure and apply patches or mitigations as needed.

Recommended defensive actions

  • Assess exposure of Linux systems to this vulnerability
  • Apply patches or mitigations provided by the Linux kernel maintainers
  • Monitor system logs for potential exploitation attempts
  • Verify Linux system exposure to this vulnerability
  • Review compensating controls for exposed systems while remediation is scheduled and verified
  • Check relevant monitoring, detection, and logs for exposed assets that need extra review
  • Track exceptions, retest remediated assets, and close the item only after evidence is documented.

Evidence notes

The CVE record and associated source item provide details on the vulnerability, including a description of the issue and affected versions. The Linux kernel maintainers have addressed this vulnerability through a series of commits. The vulnerability has a CVSS score of 5.5 and is considered MEDIUM severity. There is no information on known exploits or attacks, but defenders should verify Linux system exposure to this vulnerability and apply necessary patches or mitigations.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-64425 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-64425

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

  • CVE-2026-64425 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-64425

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

Supplemental references

  • io_uring/io-wq: re-check IO_WQ_BIT_EXIT for each linked work item

    Unverified legacy reference

    URL: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/64xxx/CVE-2026-64425.json

    cve_program_cvelist_v5

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/14b7ecad2ec56699325180a744f4b19f046401bb

    Supplemental source

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/d179533c610e1b4c6aa436e3c1fd1b719d2c727c

    Supplemental source

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/6e2f51f3e06773c2ee98ad09738f0908b48f76f9

    Supplemental source

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/ea61b04e1d7242cb37f5ed2cc91cf21a493f6597

    Supplemental source

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/b6f179a653a934736c88d820fe0098c3c2532549

    Supplemental source

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/1636d85dc139b07c0449308f2bb5e0c7a2e0da99

    Supplemental source

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/ab85765cbe3258b43dc6729af0e6ce3a87a133d8

    Supplemental source

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.