CVE-2025-21638: Linux Kernel

Medium severity, CVSS 5.5. EPSS: 0.2% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: sctp: sysctl: auth_enable: 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.

Affected products

• Linux Linux Kernel: from 3.10.41, before 3.11 (fixed in 3.11); from 3.12.20, before 3.13 (fixed in 3.13); from 3.14.5, before 5.4.290 (fixed in 5.4.290); from 5.5, before 5.10.234 (fixed in 5.10.234); from 5.11, before 5.15.177 (fixed in 5.15.177); from 5.16, before 6.1.125 (fixed in 6.1.125); …

Published 2025-01-19. Last modified 2026-07-30.