What is CVE-2025-21903?

CVE-2025-21903 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10, affecting Linux kernel versions from 6.7 onward and patched in 6.12.19, 6.13.7 and 6.14. CVE-2025-21903 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2025-21903?

CVE-2025-21903 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-2025-21903?

Yes, CVE-2025-21903 has been patched. Fixed versions include 6.12.19, 6.13.7 and 6.14. If you are running Linux kernel 6.7 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2025-21903 actively exploited?

CVE-2025-21903 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2025-21903

Medium

In the Linux kernel, the following vulnerability has been resolved: mctp i3c: handle NULL header address daddr can be NULL if there is no neighbour table entry present, in that case the tx packet should be dropped. saddr will usually be set by MCTP core, but check for NULL in case a packet is transmitted by a different protocol.

Package Linux Kernel

Published 2025-04-01

Last modified 2025-10-31

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 6.7 and later are affected. Fixed in 6.12.19, 6.13.7, 6.14 and their respective stable series.

Affected from

≥ 6.7

Fixed in

✓ 6.12.19 6.12.x ✓ 6.13.7 6.13.x ✓ 6.14

References

The following references provide additional information about CVE-2025-21903 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/740bf9c9b715cc327d34b1e2d4ee79fcd4c47a56
Patch
Kernel patch commit
https://git.kernel.org/stable/c/cf7ee25e70c6edfac4553d6b671e8b19db1d9573
Patch
Kernel patch commit
https://git.kernel.org/stable/c/d8be54c35aee29d96d1350b1b6f153be4da37c07
Patch

Details

CVE ID CVE-2025-21903

Severity Medium

CVSS score 5.5 / 10

CVSS version 3.1

Published 2025-04-01

Modified 2025-10-31

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2025-21903?

CVE-2025-21903 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10 . It affects Linux kernel versions from 6.7 onward and has been patched in 6.12.19, 6.13.7 and 6.14. CVE-2025-21903 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2025-21903?

CVE-2025-21903 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-2025-21903?

Yes — CVE-2025-21903 has been patched. Fixed versions include 6.12.19, 6.13.7 and 6.14. If you are running Linux kernel 6.7 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2025-21903 actively exploited?

No — CVE-2025-21903 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.