CVE-2025-21637 Information

Description

In the Linux kernel the following vulnerability has been resolved:

sctp: sysctl: udp_port: 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 but that would increase the size of this fix while ‘sctp.ctl_sock’ still needs to be retrieved from ’net’ structure.

Reference

https://git.kernel.org/stable/c/55627918febdf9d71107a1e68d1528dc591c9a15 https://git.kernel.org/stable/c/5b77d73f3be5102720fb685b9e6900e3500e1096 https://git.kernel.org/stable/c/c10377bbc1972d858eaf0ab366a311b39f8ef1b6 https://git.kernel.org/stable/c/e919197fb8616331f5dc81e4c3cc3d12769cb725