CVE-2025-40201 (GCVE-0-2025-40201)
Vulnerability from cvelistv5
Published
2025-11-12 21:56
Modified
2025-11-12 21:56
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
Impacted products
Vendor Product Version
Linux Linux Version: 18c91bb2d87268d23868bf13508f5bc9cf04e89a
Version: 18c91bb2d87268d23868bf13508f5bc9cf04e89a
Version: 18c91bb2d87268d23868bf13508f5bc9cf04e89a
Version: 18c91bb2d87268d23868bf13508f5bc9cf04e89a
Version: 18c91bb2d87268d23868bf13508f5bc9cf04e89a
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{
  "containers": {
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          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "kernel/sys.c"
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          "vendor": "Linux",
          "versions": [
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              "version": "5.18"
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              "version": "0",
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              "versionType": "semver"
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              "status": "unaffected",
              "version": "6.18-rc1",
              "versionType": "original_commit_for_fix"
            }
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        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
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              "cpeMatch": [
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              "operator": "OR"
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      "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."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2025-11-12T21:56:34.063Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
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          "url": "https://git.kernel.org/stable/c/1bc0d9315ef5296abb2c9fd840336255850ded18"
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        },
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          "url": "https://git.kernel.org/stable/c/19b45c84bd9fd42fa97ff80c6350d604cb871c75"
        },
        {
          "url": "https://git.kernel.org/stable/c/6796412decd2d8de8ec708213bbc958fab72f143"
        },
        {
          "url": "https://git.kernel.org/stable/c/a15f37a40145c986cdf289a4b88390f35efdecc4"
        }
      ],
      "title": "kernel/sys.c: fix the racy usage of task_lock(tsk-\u003egroup_leader) in sys_prlimit64() paths",
      "x_generator": {
        "engine": "bippy-1.2.0"
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  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-40201",
    "datePublished": "2025-11-12T21:56:34.063Z",
    "dateReserved": "2025-04-16T07:20:57.178Z",
    "dateUpdated": "2025-11-12T21:56:34.063Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2025-40201\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2025-11-12T22:15:47.283\",\"lastModified\":\"2025-11-14T16:42:30.503\",\"vulnStatus\":\"Awaiting Analysis\",\"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.\"}],\"metrics\":{},\"references\":[{\"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\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}


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