CVE-2026-64017

Status: UPDATED  |  Advisory ID: CVE-2026-64017

Key Details

Affected Products, Subsystems & Sectors

What to Know

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. (NVD)

What to Do

Monitor Linux's web page for any future patch releases.

References