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Review reviewHigh

CVE-2025-40201

Linux

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(...

CVSS
7.8
EPSS
0.14%
3.85% percentile
CISA KEV
Not listed
Published
2025.11.13
PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability0.14%
Technical severityCVSS 7.8

Vulnerability overview

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(...

Affected product and versions

Product
Linux
Affected versions
>= 18c91bb2d87268d23868bf13508f5bc9cf04e89a < 1bc0d9315ef5296abb2c9fd840336255850ded18, >= 18c91bb2d87268d23868bf13508f5bc9cf04e89a < 132f827e7bac7373e1522e89709d70b43cae5342, >= 18c91bb2d87268d23868bf13508f5bc9cf04e89a < 19b45c84bd9fd42fa97ff80c6350d604cb871c75, >= 18c91bb2d87268d23868bf13508f5bc9cf04e89a < 6796412decd2d8de8ec708213bbc958fab72f143, >= 18c91bb2d87268d23868bf13508f5bc9cf04e89a < a15f37a40145c986cdf289a4b88390f35efdecc4, >= 5.18
Fixed versions
No verified fixed-version field is available yet

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that Linux and an affected version are present.

  2. 2
    Prioritize

    Combine exploitation signals with asset exposure and business criticality.

  3. 3
    Remediate

    Follow the vendor advisory or supported update path and preserve rollback options.

  4. 4
    Verify

    Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE
Not available