# CVE-2025-39999: linux: In the Linux kernel, the following vulnerability has been resolved:  blk-mq: fix blk_mq_tags double free while nr_req...

CVE-2025-39999 is fixed in linux on 1 platform by DEBIAN-CVE-2025-39999 (version 6.16.11-1), released October 15, 2025. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2025-39999
- Priority: Routine
- CVSS: n/a
- EPSS: 0.0020
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Oct 15, 2025

## Description

In the Linux kernel, the following vulnerability has been resolved:  blk-mq: fix blk_mq_tags double free while nr_requests grown  In the case user trigger tags grow by queue sysfs attribute nr_requests, hctx->sched_tags will be freed directly and replaced with a new allocated tags, see blk_mq_tag_update_depth().  The problem is that hctx->sched_tags is from elevator->et->tags, while et->tags is still the freed tags, hence later elevator exit will try to free the tags again, causing kernel panic.  Fix this problem by replacing et->tags with new allocated tags as well.  Noted there are still some long term problems that will require some refactor to be fixed thoroughly[1].  [1] https://lore.kernel.org/all/20250815080216.410665-1-yukuai1@huaweicloud.com/

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 14 | 6.16.11-1 | [DEBIAN-CVE-2025-39999](https://patchblox.com/security/data/fix/linux/debian-cve-2025-39999.md) | Oct 15, 2025 |

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