CVE Catalog

CVE-2026-64017

HighCVSS 7.8
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.12%

2th percentile - higher than 2% of all known CVEs

Summary

A use-after-free vulnerability was found in the Linux kernel's blk-mq mechanism. The issue occurs when a task sleeps after peeking a cached request but before popping it, leading to memory being freed and potential exploitation.

Risk Assessment

An attacker could exploit this vulnerability for privilege escalation or denial of service (DoS) by manipulating block request flow, threatening system stability and security.

Recommendation

Immediately update the Linux kernel to a version containing the fix (commit addressing the flaw). For production systems, apply the security patch after testing.

Other vulnerabilities in Linux kernel

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Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: blk-mq: pop cached request if it is usable When submitting a bio to blk-mq, if the task should sleep after peeking a cached request, but before it pops it, the plug flushes and calls blk_mq_free_plug_rqs, freeing the cached_rqs. This creates a use-after-free bug. Fix this by popping the cached request before any possible blocking calls if it is suitable for use. Popping this request first holds a queue reference, so avoid any serialization races with queue freezes and can safely proceed with dispatching that request to the driver. This potentially increases a timing window from when a driver wants to freeze its queue to when requests stop being dispatched. That scenario is off the fast path though, and drivers need to appropriately handle requests during a freeze request anyway. The downside is the popped element needs to be individually freed when we performed a bio plug merge. The cached request would have had to be freed later anyway, but this patch does it inline with building the plug list instead of after flushing it.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS