What is CVE-2025-40240?

CVE-2025-40240 is a High severity Linux kernel vulnerability with a CVSS score of 7.5 out of 10, affecting Linux kernel versions from 4.8 onward and patched in 5.4.301, 5.10.246, 5.15.196 and others. CVE-2025-40240 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2025-40240?

CVE-2025-40240 has a CVSS score of 7.5 out of 10, rated High severity. The vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Is there a patch available for CVE-2025-40240?

Yes, CVE-2025-40240 has been patched. Fixed versions include 5.4.301, 5.10.246, 5.15.196 and others. If you are running Linux kernel 4.8 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2025-40240 actively exploited?

CVE-2025-40240 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2025-40240

High

In the Linux kernel, the following vulnerability has been resolved: sctp: avoid NULL dereference when chunk data buffer is missing chunk->skb pointer is dereferenced in the if-block where it's supposed to be NULL only. chunk->skb can only be NULL if chunk->head_skb is not. Check for frag_list instead and do it just before replacing chunk->skb. We're sure that otherwise chunk->skb is non-NULL because of outer if() condition.

Package Linux Kernel

Published 2025-12-04

Last modified 2026-07-30

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

7.5

out of 10

High

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

None

Availability

High

Vector string

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

Affected versions

Linux kernel versions 4.8 and later are affected. Fixed in 5.4.301, 5.10.246, 5.15.196, 6.1.158, 6.6.115, 6.12.56, 6.17.6, 6.18 and their respective stable series.

Affected from

≥ 4.8

Fixed in

✓ 5.4.301 5.4.x ✓ 5.10.246 5.10.x ✓ 5.15.196 5.15.x ✓ 6.1.158 6.1.x ✓ 6.6.115 6.6.x ✓ 6.12.56 6.12.x ✓ 6.17.6 6.17.x ✓ 6.18

References

8 total

Showing 5 of 8 references View all on NVD

Details

CVE ID CVE-2025-40240

Severity High

CVSS score 7.5 / 10

CVSS version 3.1

Published 2025-12-04

Modified 2026-07-30

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2025-40240?

CVE-2025-40240 is a High severity Linux kernel vulnerability with a CVSS score of 7.5 out of 10 . It affects Linux kernel versions from 4.8 onward and has been patched in 5.4.301, 5.10.246, 5.15.196 and others. CVE-2025-40240 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2025-40240?

CVE-2025-40240 has a CVSS score of 7.5 out of 10, rated High severity (CVSS 3.1). The vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
Is there a patch available for CVE-2025-40240?

Yes. CVE-2025-40240 has been patched. Fixed versions include 5.4.301, 5.10.246, 5.15.196 and others. If you are running Linux kernel 4.8 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2025-40240 actively exploited?

No. CVE-2025-40240 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.