CVE-2026-64017
Analyzed
Analyzed - Analysis Complete
Use-After-Free in Linux Kernel blk-mq
Vulnerability report for CVE-2026-64017, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-07-19
Last updated on: 2026-10-16
Assigner: kernel.org
Description
Description
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.
CVSS Scores
EPSS Scores
| Probability: | |
| Percentile: |
Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| linux | linux_kernel | 6.7 |
| linux | linux_kernel | 6.7 |
| linux | linux_kernel | 6.7 |
| linux | linux_kernel | 6.7 |
| linux | linux_kernel | 6.7 |
| linux | linux_kernel | 6.7 |
| linux | linux_kernel | 6.7 |
| linux | linux_kernel | 6.7 |
| linux | linux_kernel | From 6.5.13 (inc) to 6.6 (exc) |
| linux | linux_kernel | 7.1 |
| linux | linux_kernel | 7.1 |
| linux | linux_kernel | 7.1 |
| linux | linux_kernel | 7.1 |
| linux | linux_kernel | From 6.19 (inc) to 7.0.11 (exc) |
| linux | linux_kernel | From 6.1.72 (inc) to 6.2 (exc) |
| linux | linux_kernel | From 6.6.3 (inc) to 6.7 (exc) |
| linux | linux_kernel | From 6.1.75 (inc) to 6.2 (exc) |
| linux | linux_kernel | From 6.13 (inc) to 6.18.45 (exc) |
| linux | linux_kernel | From 6.6.14 (inc) to 6.7 (exc) |
| linux | linux_kernel | From 6.7.1 (inc) to 6.12.104 (exc) |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-416 | The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer. |
