What is CVE-2025-21657?

CVE-2025-21657 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10, affecting Linux kernel versions from 6.12 onward and patched in 6.12.10 and 6.13. CVE-2025-21657 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2025-21657?

CVE-2025-21657 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-2025-21657?

Yes, CVE-2025-21657 has been patched. Fixed versions include 6.12.10 and 6.13. If you are running Linux kernel 6.12 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2025-21657 actively exploited?

CVE-2025-21657 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2025-21657

Medium

In the Linux kernel, the following vulnerability has been resolved: sched_ext: Replace rq_lock() to raw_spin_rq_lock() in scx_ops_bypass() scx_ops_bypass() iterates all CPUs to re-enqueue all the scx tasks. For each CPU, it acquires a lock using rq_lock() regardless of whether a CPU is offline or the CPU is currently running a task in a higher scheduler class (e.g., deadline). The rq_lock() is supposed to be used for online CPUs, and the use of rq_lock() may trigger an unnecessary warning in rq_pin_lock(). Therefore, replace rq_lock() to raw_spin_rq_lock() in scx_ops_bypass(). Without this change, we observe the following warning: ===== START ===== [ 6.615205] rq->balance_callback && rq->balance_callback != &balance_push_callback [ 6.615208] WARNING: CPU: 2 PID: 0 at kernel/sched/sched.h:1730 __schedule+0x1130/0x1c90 ===== END =====

Package Linux Kernel

Published 2025-01-21

Last modified 2025-10-15

CVSS version 3.1

Patch available

Yes

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

Affected versions

Linux kernel versions 6.12 and later are affected. Fixed in 6.12.10, 6.13 and their respective stable series.

Affected from

≥ 6.12

Fixed in

✓ 6.12.10 6.12.x ✓ 6.13

References

The following references provide additional information about CVE-2025-21657 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/6268d5bc10354fc2ab8d44a0cd3b042d49a0417e
Patch
Kernel patch commit
https://git.kernel.org/stable/c/d9e446dd63cee7161717a6a8414ba9c6435af764
Patch

Details

CVE ID CVE-2025-21657

Severity Medium

CVSS score 5.5 / 10

CVSS version 3.1

Published 2025-01-21

Modified 2025-10-15

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2025-21657?

CVE-2025-21657 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10 . It affects Linux kernel versions from 6.12 onward and has been patched in 6.12.10 and 6.13. CVE-2025-21657 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2025-21657?

CVE-2025-21657 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-2025-21657?

Yes — CVE-2025-21657 has been patched. Fixed versions include 6.12.10 and 6.13. If you are running Linux kernel 6.12 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2025-21657 actively exploited?

No — CVE-2025-21657 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.