NULL Pointer Dereference The advisory has been revoked - it doesn't affect any version of package kernel-headers  (opens in a new tab)


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  • Snyk IDSNYK-RHEL10-KERNELHEADERS-12464484
  • published3 Sept 2025
  • disclosed19 Jan 2025

Introduced: 19 Jan 2025

CVE-2025-21640  (opens in a new tab)
CWE-476  (opens in a new tab)

Amendment

The Red Hat security team deemed this advisory irrelevant for RHEL:10.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-headers package and not the kernel-headers package as distributed by RHEL.

In the Linux kernel, the following vulnerability has been resolved:

sctp: sysctl: cookie_hmac_alg: avoid using current->nsproxy

As mentioned in a previous commit of this series, using the 'net' structure via 'current' is not recommended for different reasons:

  • Inconsistency: getting info from the reader's/writer's netns vs only from the opener's netns.

  • current->nsproxy can be NULL in some cases, resulting in an 'Oops' (null-ptr-deref), e.g. when the current task is exiting, as spotted by syzbot [1] using acct(2).

The 'net' structure can be obtained from the table->data using container_of().

Note that table->data could also be used directly, as this is the only member needed from the 'net' structure, but that would increase the size of this fix, to use '*data' everywhere 'net->sctp.sctp_hmac_alg' is used.