What is CVE-2025-40204?

CVE-2025-40204 is a High severity Linux kernel vulnerability with a CVSS score of 8.1 out of 10, affecting Linux kernel versions from 2.6.12 onward and patched in 5.4.301, 5.10.246, 5.15.195 and others. CVE-2025-40204 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2025-40204?

CVE-2025-40204 has a CVSS score of 8.1 out of 10, rated High severity. The vector string is CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H.

Is there a patch available for CVE-2025-40204?

Yes, CVE-2025-40204 has been patched. Fixed versions include 5.4.301, 5.10.246, 5.15.195 and others. If you are running Linux kernel 2.6.12 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2025-40204 actively exploited?

CVE-2025-40204 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2025-40204

High

In the Linux kernel, the following vulnerability has been resolved: sctp: Fix MAC comparison to be constant-time To prevent timing attacks, MACs need to be compared in constant time. Use the appropriate helper function for this.

Package Linux Kernel

Published 2025-11-12

Last modified 2026-07-30

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

8.1

out of 10

High

Attack Vector

Network

Attack Complexity

High

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Vector string

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

Affected versions

Linux kernel versions 2.6.12 and later are affected. Fixed in 5.4.301, 5.10.246, 5.15.195, 6.1.157, 6.6.113, 6.12.54, 6.17.4, 6.18 and their respective stable series.

Affected from

≥ 2.6.12

Fixed in

✓ 5.4.301 5.4.x ✓ 5.10.246 5.10.x ✓ 5.15.195 5.15.x ✓ 6.1.157 6.1.x ✓ 6.6.113 6.6.x ✓ 6.12.54 6.12.x ✓ 6.17.4 6.17.x ✓ 6.18

References

8 total

Showing 5 of 8 references View all on NVD

Details

CVE ID CVE-2025-40204

Severity High

CVSS score 8.1 / 10

CVSS version 3.1

Published 2025-11-12

Modified 2026-07-30

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2025-40204?

CVE-2025-40204 is a High severity Linux kernel vulnerability with a CVSS score of 8.1 out of 10 . It affects Linux kernel versions from 2.6.12 onward and has been patched in 5.4.301, 5.10.246, 5.15.195 and others. CVE-2025-40204 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2025-40204?

CVE-2025-40204 has a CVSS score of 8.1 out of 10, rated High severity (CVSS 3.1). The vector string is CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H.
Is there a patch available for CVE-2025-40204?

Yes. CVE-2025-40204 has been patched. Fixed versions include 5.4.301, 5.10.246, 5.15.195 and others. If you are running Linux kernel 2.6.12 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2025-40204 actively exploited?

No. CVE-2025-40204 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.