CVE-2025-40240: In the Linux kernel, the following vulnerability has been resolved: sctp: avoid NULL dereference when chunk data buffer is missing chunk->skb pointe...

Description

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.

Metrics

EPSS Probability

0.18%

7.4th percentile

Probability of exploitation in the next 30 days. Learn more

References

Timeline

Published: Dec 4, 2025
Last Modified: Jun 17, 2026
Status: Deferred

Frequently Asked Questions

What is CVE-2025-40240?

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.

How severe is CVE-2025-40240?

Severity scoring for CVE-2025-40240 is pending analysis. The EPSS model estimates a 0.18% probability of exploitation in the next 30 days.

How do I fix CVE-2025-40240?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.