{"id":"CVE-2025-40201","title":"kernel/sys.c: fix the racy usage of task_lock(tsk->group_leader) in sys_prlimit64() paths","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nkernel/sys.c: fix the racy usage of task_lock(tsk->group_leader) in sys_prlimit64() paths\n\nThe usage of task_lock(tsk->group_leader) in sys_prlimit64()->do_prlimit()\npa…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= 18c91bb2d87268d23868bf13508f5bc9cf04e89a < 1bc0d9315ef5296abb2c9fd840336255850ded18","Linux >= 18c91bb2d87268d23868bf13508f5bc9cf04e89a < 132f827e7bac7373e1522e89709d70b43cae5342","Linux >= 18c91bb2d87268d23868bf13508f5bc9cf04e89a < 19b45c84bd9fd42fa97ff80c6350d604cb871c75","Linux >= 18c91bb2d87268d23868bf13508f5bc9cf04e89a < 6796412decd2d8de8ec708213bbc958fab72f143","Linux >= 18c91bb2d87268d23868bf13508f5bc9cf04e89a < a15f37a40145c986cdf289a4b88390f35efdecc4","Linux 5.18"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-10-15T21:58:02.275858Z"},"published":"2025-11-12","updated":"2026-10-15","sourceUpdated":"2026-10-15T22:02:40.564Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2025-40201","references":[{"url":"https://git.kernel.org/stable/c/1bc0d9315ef5296abb2c9fd840336255850ded18"},{"url":"https://git.kernel.org/stable/c/132f827e7bac7373e1522e89709d70b43cae5342"},{"url":"https://git.kernel.org/stable/c/19b45c84bd9fd42fa97ff80c6350d604cb871c75"},{"url":"https://git.kernel.org/stable/c/6796412decd2d8de8ec708213bbc958fab72f143"},{"url":"https://git.kernel.org/stable/c/a15f37a40145c986cdf289a4b88390f35efdecc4"}],"tags":["cve.org"],"epss":0.00153,"epssPercentile":0.03958,"ingestedAt":"2026-10-15T22:48:25.551Z","slug":"CVE-2025-40201","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nkernel/sys.c: fix the racy usage of task_lock(tsk->group_leader) in sys_prlimit64() paths\n\nThe usage of task_lock(tsk->group_leader) in sys_prlimit64()->do_prlimit()\npath is very broken.\n\nsys_prlimit64() does get_task_struct(tsk) but this only protects task_struct\nitself. If tsk != current and tsk is not a leader, this process can exit/exec\nand task_lock(tsk->group_leader) may use the already freed task_struct.\n\nAnother problem is that sys_prlimit64() can race with mt-exec which changes\n->group_leader. In this case do_prlimit() may take the wrong lock, or (worse)\n->group_leader may change between task_lock() and task_unlock().\n\nChange sys_prlimit64() to take tasklist_lock when necessary. This is not\nnice, but I don't see a better fix for -stable.\n\n## Affected\n\n- `Linux >= 18c91bb2d87268d23868bf13508f5bc9cf04e89a < 1bc0d9315ef5296abb2c9fd840336255850ded18`\n- `Linux >= 18c91bb2d87268d23868bf13508f5bc9cf04e89a < 132f827e7bac7373e1522e89709d70b43cae5342`\n- `Linux >= 18c91bb2d87268d23868bf13508f5bc9cf04e89a < 19b45c84bd9fd42fa97ff80c6350d604cb871c75`\n- `Linux >= 18c91bb2d87268d23868bf13508f5bc9cf04e89a < 6796412decd2d8de8ec708213bbc958fab72f143`\n- `Linux >= 18c91bb2d87268d23868bf13508f5bc9cf04e89a < a15f37a40145c986cdf289a4b88390f35efdecc4`\n- `Linux 5.18`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}