Linux Kernel SCTP Chunk NULL Derefer when Data Buffer Missing
CVE-2025-40240 Published on December 4, 2025
sctp: avoid NULL dereference when chunk data buffer is missing
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.
Products Associated with CVE-2025-40240
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Affected Versions
Linux:- Version 90017accff61ae89283ad9a51f9ac46ca01633fb and below 61cda2777b07d27459f5cac5a047c3edf9c8a1a9 is affected.
- Version 90017accff61ae89283ad9a51f9ac46ca01633fb and below 08165c296597075763130919f2aae59b5822f016 is affected.
- Version 90017accff61ae89283ad9a51f9ac46ca01633fb and below 03e80a4b04ef1fb2c61dd63216ab8d3a5dcb196f is affected.
- Version 90017accff61ae89283ad9a51f9ac46ca01633fb and below 4f6da435fb5d8a21cbf8cae5ca5a2ba0e1012b71 is affected.
- Version 90017accff61ae89283ad9a51f9ac46ca01633fb and below cb9055ba30306ede4ad920002233d0659982f1cb is affected.
- Version 90017accff61ae89283ad9a51f9ac46ca01633fb and below 7a832b0f99be19df608cb75c023f8027b1789bd1 is affected.
- Version 90017accff61ae89283ad9a51f9ac46ca01633fb and below 89b465b54227c245ddc7cc9ed822231af21123ef is affected.
- Version 90017accff61ae89283ad9a51f9ac46ca01633fb and below 441f0647f7673e0e64d4910ef61a5fb8f16bfb82 is affected.
- Version 4.8 is affected.
- Before 4.8 is unaffected.
- Version 5.4.301, <= 5.4.* is unaffected.
- Version 5.10.246, <= 5.10.* is unaffected.
- Version 5.15.196, <= 5.15.* is unaffected.
- Version 6.1.158, <= 6.1.* is unaffected.
- Version 6.6.115, <= 6.6.* is unaffected.
- Version 6.12.56, <= 6.12.* is unaffected.
- Version 6.17.6, <= 6.17.* is unaffected.
- Version 6.18, <= * is unaffected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.