CVE-2026-64017
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.
- Published Jul 19, 2026
- CVSS 7.8 high
- 0.1% chance of exploitation in the next 30 days (EPSS)
- A fix is available
Affected software
In the news
- Multiple vulnerabilities in the Ubuntu Linux kernel CERT-FR ·
- Multiple vulnerabilities in the SUSE Linux kernel CERT-FR ·
- Multiple vulnerabilities in the Debian LTS Linux kernel CERT-FR ·
- Multiple vulnerabilities in the Red Hat Linux kernel CERT-FR ·
- Multiple vulnerabilities in the Ubuntu Linux kernel CERT-FR ·