What is CVE-2025-21817?

CVE-2025-21817 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10, classified as a Improper Locking flaw (CWE-667), affecting Linux kernel versions from 6.13.2 onward. CVE-2025-21817 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2025-21817?

CVE-2025-21817 has a CVSS score of 5.5 out of 10, rated Medium severity. The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

Is there a patch available for CVE-2025-21817?

No patch is currently available for CVE-2025-21817. Monitor the NIST NVD and your Linux distribution's security advisories for updates.

Is CVE-2025-21817 actively exploited?

CVE-2025-21817 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is Improper Locking (CWE-667)?

The product does not properly acquire or release a lock, which can lead to unexpected behaviour. See MITRE CWE for full details: https://cwe.mitre.org/data/definitions/667.html

CVE-2025-21817

Medium

In the Linux kernel, the following vulnerability has been resolved: block: mark GFP_NOIO around sysfs ->store() sysfs ->store is called with queue freezed, meantime we have several ->store() callbacks(update_nr_requests, wbt, scheduler) to allocate memory with GFP_KERNEL which may run into direct reclaim code path, then potential deadlock can be caused. Fix the issue by marking NOIO around sysfs ->store()

Package Linux Kernel

Published 2025-02-27

Last modified 2025-10-28

CVSS version 3.1

Patch available

Not yet patched

CVSS 3.1 score

5.5

out of 10

Medium

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

None

Availability

High

Vector string

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Weakness type

CWE-667

CVE-2025-21817 is a Improper Locking vulnerability

What is Improper Locking?

The product does not properly acquire or release a lock, which can lead to unexpected behaviour. Learn more on MITRE CWE

Affected versions

Linux kernel versions 6.13.2 and later are affected. No fixed version recorded yet.

Affected from

≥ 6.13.2

References

The following references provide additional information about CVE-2025-21817 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.

Kernel patch commit
https://git.kernel.org/stable/c/2566ce907e5d5db8a039647208e029ce559baa31
Patch
Kernel patch commit
https://git.kernel.org/stable/c/7c0be4ead1f8f5f8be0803f347de0de81e3b8e1c
Patch

Details

CVE ID CVE-2025-21817

Severity Medium

CVSS score 5.5 / 10

CVSS version 3.1

Published 2025-02-27

Modified 2025-10-28

KEV No

Patch

Not yet patched

Package linux

Frequently asked questions

What is CVE-2025-21817?

CVE-2025-21817 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10 , classified as an Improper Locking flaw (CWE-667) . It affects Linux kernel versions from 6.13.2 onward . CVE-2025-21817 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2025-21817?

CVE-2025-21817 has a CVSS score of 5.5 out of 10, rated Medium severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.
Is there a patch available for CVE-2025-21817?

No patch is currently available for CVE-2025-21817. Monitor the NIST NVD and your Linux distribution's security advisories for updates.
Is CVE-2025-21817 actively exploited?

No — CVE-2025-21817 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.
What is Improper Locking (CWE-667)?

The product does not properly acquire or release a lock, which can lead to unexpected behaviour. View CWE-667 on MITRE CWE →