CVE-2025-21642

Name of the Vulnerable Software and Affected Versions Linux kernel versions prior to 6.6.74

Description The issue is related to the use of the 'net' structure via 'current' in the Linux kernel, which is not recommended due to inconsistencies with how generic sysctl entries are handled and potential null pointer dereferences when accessing current->nsproxy->netns. This can lead to general protection faults, as observed by syzbot when using acct(2). The vulnerability is resolved by avoiding the use of current->nsproxy in the mptcp sysctl sched.

Recommendations To resolve the issue, update the Linux kernel to version 6.6.74 or later. As a temporary workaround, consider restricting access to the vulnerable sysctl entries until a patch is available.