What is CVE-2025-39921?

CVE-2025-39921 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10, affecting Linux kernel versions from 6.14 onward and patched in 6.16.6 and 6.17. CVE-2025-39921 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2025-39921?

CVE-2025-39921 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-2025-39921?

Yes, CVE-2025-39921 has been patched. Fixed versions include 6.16.6 and 6.17. If you are running Linux kernel 6.14 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2025-39921 actively exploited?

CVE-2025-39921 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2025-39921

Medium

In the Linux kernel, the following vulnerability has been resolved: spi: microchip-core-qspi: stop checking viability of op->max_freq in supports_op callback In commit 13529647743d9 ("spi: microchip-core-qspi: Support per spi-mem operation frequency switches") the logic for checking the viability of op->max_freq in mchp_coreqspi_setup_clock() was copied into mchp_coreqspi_supports_op(). Unfortunately, op->max_freq is not valid when this function is called during probe but is instead zero. Accordingly, baud_rate_val is calculated to be INT_MAX due to division by zero, causing probe of the attached memory device to fail. Seemingly spi-microchip-core-qspi was the only driver that had such a modification made to its supports_op callback when the per_op_freq capability was added, so just remove it to restore prior functionality.

Package Linux Kernel

Published 2025-10-01

Last modified 2026-01-14

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 6.14 and later are affected. Fixed in 6.16.6, 6.17 and their respective stable series.

Affected from

≥ 6.14

Fixed in

✓ 6.16.6 6.16.x ✓ 6.17

References

The following references provide additional information about CVE-2025-39921 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/89e7353f522f5cf70cb48c01ce2dcdcb275b8022
Patch
Kernel patch commit
https://git.kernel.org/stable/c/ac8a13f35d5b8996582b3f97b924838a5c570c18
Patch

Details

CVE ID CVE-2025-39921

Severity Medium

CVSS score 5.5 / 10

CVSS version 3.1

Published 2025-10-01

Modified 2026-01-14

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2025-39921?

CVE-2025-39921 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10 . It affects Linux kernel versions from 6.14 onward and has been patched in 6.16.6 and 6.17. CVE-2025-39921 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2025-39921?

CVE-2025-39921 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-2025-39921?

Yes — CVE-2025-39921 has been patched. Fixed versions include 6.16.6 and 6.17. If you are running Linux kernel 6.14 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2025-39921 actively exploited?

No — CVE-2025-39921 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.