CVE-2025-40240
Published Dec 4, 2025
Modified Apr 15, 2026
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.
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References
Other References
https://git.kernel.org/stable/c/03e80a4b04ef1fb2c61dd63216ab8d3a5dcb196f
https://git.kernel.org/stable/c/08165c296597075763130919f2aae59b5822f016
https://git.kernel.org/stable/c/441f0647f7673e0e64d4910ef61a5fb8f16bfb82
https://git.kernel.org/stable/c/4f6da435fb5d8a21cbf8cae5ca5a2ba0e1012b71
https://git.kernel.org/stable/c/61cda2777b07d27459f5cac5a047c3edf9c8a1a9
https://git.kernel.org/stable/c/7a832b0f99be19df608cb75c023f8027b1789bd1
https://git.kernel.org/stable/c/89b465b54227c245ddc7cc9ed822231af21123ef
https://git.kernel.org/stable/c/cb9055ba30306ede4ad920002233d0659982f1cb
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 do I check if I'm vulnerable to CVE-2025-40240? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.