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CVE-2022-50221

Estado: ModificadaAlta (7.1)—

In the Linux kernel, the following vulnerability has been resolved:

drm/fb-helper: Fix out-of-bounds access

Clip memory range to screen-buffer size to avoid out-of-bounds access in fbdev deferred I/O's damage handling.

Fbdev's deferred I/O can only track pages. From the range of pages, the damage handler computes the clipping rectangle for the display update. If the fbdev screen buffer ends near the beginning of a page, that page could contain more scanlines. The damage handler would then track these non-existing scanlines as dirty and provoke an out-of-bounds access during the screen update. Hence, clip the maximum memory range to the size of the screen buffer.

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While at it, rename the variables min/max to min_off/max_off in drm_fb_helper_deferred_io(). This avoids confusion with the macros of the same name.

CVSS

Probabilidad de explotación (EPSS)

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

Vulnerabilidad local (AV:L) sin interacción requerida (UI:N) en kernel Linux que permite escalada de privilegios mediante acceso fuera de límites (CWE-125) en manejador de daños de fbdev; podría conducir a ejecución de código con privilegios elevados.

Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Execution PreventionThreat Intelligence ProgramRestrict Web-Based ContentPrivileged Account ManagementLimit Software InstallationBehavior Prevention on Endpoint

Tecnologías afectadas (1)

Linux — Linux Kernel

CWE

Referencias

JSON original (NVD)

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  "id": "CVE-2022-50221",
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  "published": "2025-06-18T11:15:53.090",
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  "weaknesses": [
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          "value": "CWE-125"
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      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/fb-helper: Fix out-of-bounds access\n\nClip memory range to screen-buffer size to avoid out-of-bounds access\nin fbdev deferred I/O's damage handling.\n\nFbdev's deferred I/O can only track pages. From the range of pages, the\ndamage handler computes the clipping rectangle for the display update.\nIf the fbdev screen buffer ends near the beginning of a page, that page\ncould contain more scanlines. The damage handler would then track these\nnon-existing scanlines as dirty and provoke an out-of-bounds access\nduring the screen update. Hence, clip the maximum memory range to the\nsize of the screen buffer.\n\nWhile at it, rename the variables min/max to min_off/max_off in\ndrm_fb_helper_deferred_io(). This avoids confusion with the macros of\nthe same name."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: drm/fb-helper: Arregla el acceso fuera de los límites Recorta el rango de memoria al tamaño del búfer de pantalla para evitar el acceso fuera de los límites en el manejo de daños de E/S diferidas de fbdev. La E/S diferida de fbdev solo puede rastrear páginas. A partir del rango de páginas, el controlador de daños calcula el rectángulo de recorte para la actualización de la pantalla. Si el búfer de pantalla de fbdev termina cerca del principio de una página, esa página podría contener más líneas de exploración. El controlador de daños rastrearía entonces estas líneas de exploración inexistentes como sucias y provocaría un acceso fuera de los límites durante la actualización de la pantalla. Por lo tanto, recorta el rango máximo de memoria al tamaño del búfer de pantalla. Mientras lo haces, cambia el nombre de las variables min/max a min_off/max_off en drm_fb_helper_deferred_io(). Esto evita confusiones con las macros del mismo nombre."
    }
  ],
  "lastModified": "2026-08-04T10:18:07.687",
  "configurations": [
    {
      "nodes": [
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          "negate": false,
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              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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}