CVE-2025-40201 - kernel/sys.c: fix the racy usage of task_lock(tsk->group_leader) in sys_prlimit64() paths

CVE-2025-40201 - kernel/sys.c: fix the racy usage of task_lock(tsk->group_leader) in sys_prlimit64() paths

https://cvefeed.io/rssfeed/latest.atom / Thu, 11/13/2025 - 01:48
CVE ID : CVE-2025-40201
Published : Nov. 12, 2025, 10:15 p.m. | 2 hours, 32 minutes ago
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.
Severity: 0.0 | NA
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