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

sctp: sysctl: rto_min/max: 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.rto_min/max' is used.

References

• https://nvd.nist.gov/vuln/detail/CVE-2025-21639
• https://git.kernel.org/stable/c/4059507e34aa5fe0fa9fd5b2b5f0c8b26ab2d482
• https://git.kernel.org/stable/c/9fc17b76fc70763780aa78b38fcf4742384044a5
• https://git.kernel.org/stable/c/c87f1f6ade56c711f8736901e330685b453e420e
• https://git.kernel.org/stable/c/dc9d0e3cfd16f66fbf0862857c6b391c8613ca9f
• https://git.kernel.org/stable/c/0f78f09466744589e420935e646ae78212a38290