CVE-2025-40201: In the Linux kernel, the following vulnerability has been resolved: kernel/sys.c: fix the racy usage of task_lock(tsk->group_leader) in sys_prlimit64...

Description

In the Linux kernel, the following vulnerability has been resolved: kernel/sys.c: fix the racy usage of task_lock(tsk->group_leader) in sys_prlimit64() paths The usage of task_lock(tsk->group_leader) in sys_prlimit64()->do_prlimit() path is very broken. sys_prlimit64() does get_task_struct(tsk) but this only protects task_struct itself. If tsk != current and tsk is not a leader, this process can exit/exec and task_lock(tsk->group_leader) may use the already freed task_struct. Another problem is that sys_prlimit64() can race with mt-exec which changes ->group_leader. In this case do_prlimit() may take the wrong lock, or (worse) ->group_leader may change between task_lock() and task_unlock(). Change sys_prlimit64() to take tasklist_lock when necessary. This is not nice, but I don't see a better fix for -stable.

Metrics

EPSS Probability

0.16%

5.8th percentile

Probability of exploitation in the next 30 days. Learn more

References

Timeline

Published: Nov 12, 2025
Last Modified: Jun 17, 2026
Status: Deferred

Frequently Asked Questions

What is CVE-2025-40201?

In the Linux kernel, the following vulnerability has been resolved: kernel/sys.c: fix the racy usage of task_lock(tsk->group_leader) in sys_prlimit64() paths The usage of task_lock(tsk->group_leader) in sys_prlimit64()->do_prlimit() path is very broken. sys_prlimit64() does get_task_struct(tsk) but this only protects task_struct itself. If tsk != current and tsk is not a leader, this process can exit/exec and task_lock(tsk->group_leader) may use the already freed task_struct. Another problem is that sys_prlimit64() can race with mt-exec which changes ->group_leader. In this case do_prlimit() may take the wrong lock, or (worse) ->group_leader may change between task_lock() and task_unlock(). Change sys_prlimit64() to take tasklist_lock when necessary. This is not nice, but I don't see a better fix for -stable.

How severe is CVE-2025-40201?

Severity scoring for CVE-2025-40201 is pending analysis. The EPSS model estimates a 0.16% probability of exploitation in the next 30 days.

How do I fix CVE-2025-40201?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.