FKIE_CVE-2025-40201

Vulnerability from fkie_nvd - Published: 2025-11-12 22:15 - Updated: 2026-06-17 09:21
Severity
Summary
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.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/132f827e7bac7373e1522e89709d70b43cae5342
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/19b45c84bd9fd42fa97ff80c6350d604cb871c75
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1bc0d9315ef5296abb2c9fd840336255850ded18
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6796412decd2d8de8ec708213bbc958fab72f143
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/a15f37a40145c986cdf289a4b88390f35efdecc4
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "kernel/sys.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "1bc0d9315ef5296abb2c9fd840336255850ded18",
              "status": "affected",
              "version": "18c91bb2d87268d23868bf13508f5bc9cf04e89a",
              "versionType": "git"
            },
            {
              "lessThan": "132f827e7bac7373e1522e89709d70b43cae5342",
              "status": "affected",
              "version": "18c91bb2d87268d23868bf13508f5bc9cf04e89a",
              "versionType": "git"
            },
            {
              "lessThan": "19b45c84bd9fd42fa97ff80c6350d604cb871c75",
              "status": "affected",
              "version": "18c91bb2d87268d23868bf13508f5bc9cf04e89a",
              "versionType": "git"
            },
            {
              "lessThan": "6796412decd2d8de8ec708213bbc958fab72f143",
              "status": "affected",
              "version": "18c91bb2d87268d23868bf13508f5bc9cf04e89a",
              "versionType": "git"
            },
            {
              "lessThan": "a15f37a40145c986cdf289a4b88390f35efdecc4",
              "status": "affected",
              "version": "18c91bb2d87268d23868bf13508f5bc9cf04e89a",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "kernel/sys.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.18"
            },
            {
              "lessThan": "5.18",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.157",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.113",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.54",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.17.*",
              "status": "unaffected",
              "version": "6.17.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.18",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nkernel/sys.c: fix the racy usage of task_lock(tsk-\u003egroup_leader) in sys_prlimit64() paths\n\nThe usage of task_lock(tsk-\u003egroup_leader) in sys_prlimit64()-\u003edo_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-\u003egroup_leader) may use the already freed task_struct.\n\nAnother problem is that sys_prlimit64() can race with mt-exec which changes\n-\u003egroup_leader. In this case do_prlimit() may take the wrong lock, or (worse)\n-\u003egroup_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\u0027t see a better fix for -stable."
    }
  ],
  "id": "CVE-2025-40201",
  "lastModified": "2026-06-17T09:21:26.980",
  "metrics": {},
  "published": "2025-11-12T22:15:47.283",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/132f827e7bac7373e1522e89709d70b43cae5342"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/19b45c84bd9fd42fa97ff80c6350d604cb871c75"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/1bc0d9315ef5296abb2c9fd840336255850ded18"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/6796412decd2d8de8ec708213bbc958fab72f143"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/a15f37a40145c986cdf289a4b88390f35efdecc4"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Deferred"
}


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