FKIE_CVE-2026-23380

Vulnerability from fkie_nvd - Published: 2026-03-25 11:16 - Updated: 2026-04-24 16:28
Severity ?
5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: tracing: Fix WARN_ON in tracing_buffers_mmap_close When a process forks, the child process copies the parent's VMAs but the user_mapped reference count is not incremented. As a result, when both the parent and child processes exit, tracing_buffers_mmap_close() is called twice. On the second call, user_mapped is already 0, causing the function to return -ENODEV and triggering a WARN_ON. Normally, this isn't an issue as the memory is mapped with VM_DONTCOPY set. But this is only a hint, and the application can call madvise(MADVISE_DOFORK) which resets the VM_DONTCOPY flag. When the application does that, it can trigger this issue on fork. Fix it by incrementing the user_mapped reference count without re-mapping the pages in the VMA's open callback.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/91f3e8d84c89918769e71393f839c9fefadc2580Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b0f269ba6fefe9e3cb9feedcf78fcd0b633800c0Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/cdd96641b64297a2db42676f051362b76280a58bPatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/e39bb9e02b68942f8e9359d2a3efe7d37ae6be0ePatch
Impacted products
Vendor Product Version
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
linux linux_kernel 6.10
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel 7.0
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  "descriptions": [
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      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntracing: Fix WARN_ON in tracing_buffers_mmap_close\n\nWhen a process forks, the child process copies the parent\u0027s VMAs but the\nuser_mapped reference count is not incremented. As a result, when both the\nparent and child processes exit, tracing_buffers_mmap_close() is called\ntwice. On the second call, user_mapped is already 0, causing the function to\nreturn -ENODEV and triggering a WARN_ON.\n\nNormally, this isn\u0027t an issue as the memory is mapped with VM_DONTCOPY set.\nBut this is only a hint, and the application can call\nmadvise(MADVISE_DOFORK) which resets the VM_DONTCOPY flag. When the\napplication does that, it can trigger this issue on fork.\n\nFix it by incrementing the user_mapped reference count without re-mapping\nthe pages in the VMA\u0027s open callback."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\ntracing: Correcci\u00f3n de WARN_ON en tracing_buffers_mmap_close\n\nCuando un proceso hace fork, el proceso hijo copia los VMAs del padre pero el contador de referencias user_mapped no se incrementa. Como resultado, cuando tanto el proceso padre como el hijo terminan, tracing_buffers_mmap_close() se llama dos veces. En la segunda llamada, user_mapped ya es 0, lo que hace que la funci\u00f3n devuelva -ENODEV y active un WARN_ON.\n\nNormalmente, esto no es un problema ya que la memoria est\u00e1 mapeada con VM_DONTCOPY establecido. Pero esto es solo una sugerencia, y la aplicaci\u00f3n puede llamar a madvise(MADVISE_DOFORK) lo que restablece el flag VM_DONTCOPY. Cuando la aplicaci\u00f3n hace eso, puede activar este problema al hacer fork.\n\nSe soluciona incrementando el contador de referencias user_mapped sin remapear las p\u00e1ginas en la funci\u00f3n de callback \u0027open\u0027 del VMA."
    }
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  "id": "CVE-2026-23380",
  "lastModified": "2026-04-24T16:28:47.850",
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          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 5.5,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
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          "userInteraction": "NONE",
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  "published": "2026-03-25T11:16:38.017",
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