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Review reviewHigh

CVE-2025-40240

Linux

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.

CVSS
7.5
EPSS
0.59%
44.7% percentile
CISA KEV
Not listed
Published
2025.12.05
PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability0.59%
Technical severityCVSS 7.5

Vulnerability overview

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.

Affected product and versions

Product
Linux
Affected versions
>= 90017accff61ae89283ad9a51f9ac46ca01633fb < 61cda2777b07d27459f5cac5a047c3edf9c8a1a9, >= 90017accff61ae89283ad9a51f9ac46ca01633fb < 08165c296597075763130919f2aae59b5822f016, >= 90017accff61ae89283ad9a51f9ac46ca01633fb < 03e80a4b04ef1fb2c61dd63216ab8d3a5dcb196f, >= 90017accff61ae89283ad9a51f9ac46ca01633fb < 4f6da435fb5d8a21cbf8cae5ca5a2ba0e1012b71, >= 90017accff61ae89283ad9a51f9ac46ca01633fb < cb9055ba30306ede4ad920002233d0659982f1cb, >= 90017accff61ae89283ad9a51f9ac46ca01633fb < 7a832b0f99be19df608cb75c023f8027b1789bd1, >= 90017accff61ae89283ad9a51f9ac46ca01633fb < 89b465b54227c245ddc7cc9ed822231af21123ef, >= 90017accff61ae89283ad9a51f9ac46ca01633fb < 441f0647f7673e0e64d4910ef61a5fb8f16bfb82, >= 4.8
Fixed versions
No verified fixed-version field is available yet

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that Linux and an affected version are present.

  2. 2
    Prioritize

    Combine exploitation signals with asset exposure and business criticality.

  3. 3
    Remediate

    Follow the vendor advisory or supported update path and preserve rollback options.

  4. 4
    Verify

    Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE
Not available