CVE-2025-39999
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_requ…
Overview
CVE-2025-39999 is a known-severity vulnerability. It was published on October 15, 2025.
Technical 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/[email protected]/
Remediation
Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
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Frequently asked questions
What is CVE-2025-39999?
CVE-2025-39999 is a known-severity vulnerability. It was published on October 15, 2025.
How severe is CVE-2025-39999?
CVSS score information is not yet available for this vulnerability. Check back as the CVE record is updated by NVD analysts.
How do I fix or remediate CVE-2025-39999?
Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2025-39999?
CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2025-39999 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.