Answer in brief
CVE-2025-40201 records a High severity (CVSS 7.8) vulnerability in kernel/sys.c: fix the racy usage of task_lock(tsk->group_leader) in sys_prlimit64() paths. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 7.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=18c91bb2d87268d23868bf13508f5bc9cf04e89a <1bc0d9315ef5296abb2c9fd840336255850ded18 || >=18c91bb2d87268d23868bf13508f5bc9cf04e89a <132f827e7bac7373e1522e89709d70b43cae5342 || >=18c91bb2d87268d23868bf13508f5bc9cf04e89a <19b45c84bd9fd42fa97ff80c6350d604cb871c75 || >=18c91bb2d87268d23868bf13508f5bc9cf04e89a <6796412decd2d8de8ec708213bbc958fab72f143 || >=18c91bb2d87268d23868bf13508f5bc9cf04e89a <a15f37a40145c986cdf289a4b88390f35efdecc4 | 1bc0d9315ef5296abb2c9fd840336255850ded18, 132f827e7bac7373e1522e89709d70b43cae5342, 19b45c84bd9fd42fa97ff80c6350d604cb871c75, 6796412decd2d8de8ec708213bbc958fab72f143, a15f37a40145c986cdf289a4b88390f35efdecc4 |
| Linux/Linuxgeneric | 5.18 | Not reported |
Published upstream
Nov 12, 2025
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 19, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 5, 2026
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.
Quoted source text, attributed separately from HOL analysis.