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CVE-2026-17556

Full vulnerability record from the local CVENow database.

Description

A path traversal vulnerability was identified in GitHub Enterprise Server that allowed an unauthenticated attacker to delete arbitrary files and directories on the instance, including the entire user storage directory containing Git LFS objects, release assets, attachments, and avatars. The X-GitHub-Request-Id request header was used without sanitization as a filesystem path segment for the upload buffer directory, so a traversal value pointed the buffer at an arbitrary path and the deferred cleanup routine recursively removed the traversed target. Exploitation required only network reachability to the instance and no authentication, and it worked even when private mode was enabled. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.22 and was fixed in versions 3.21.4, 3.20.6, 3.19.10, 3.18.13 and 3.17.19. This vulnerability was reported via the GitHub Bug Bounty program.

Severity
HIGH
CVSS score
8.8 (v4.0)
Vulnerability status
Analyzed
Source identifier
[email protected]
Published
2026-08-05 20:17:06.047000
Last modified
2026-10-23 21:10:00.157000
View original CVE JSON 
{
  "id": "CVE-2026-17556",
  "sourceIdentifier": "[email protected]",
  "published": "2026-08-05T20:17:06.047",
  "lastModified": "2026-10-23T21:10:00.157",
  "vulnStatus": "Analyzed",
  "cveTags": [],
  "descriptions": [
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      "value": "A path traversal vulnerability was identified in GitHub Enterprise Server that allowed an unauthenticated attacker to delete arbitrary files and directories on the instance, including the entire user storage directory containing Git LFS objects, release assets, attachments, and avatars. The X-GitHub-Request-Id request header was used without sanitization as a filesystem path segment for the upload buffer directory, so a traversal value pointed the buffer at an arbitrary path and the deferred cleanup routine recursively removed the traversed target. Exploitation required only network reachability to the instance and no authentication, and it worked even when private mode was enabled. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.22 and was fixed in versions 3.21.4, 3.20.6, 3.19.10, 3.18.13 and 3.17.19. This vulnerability was reported via the GitHub Bug Bounty program."
    },
    {
      "lang": "es",
      "value": "Una vulnerabilidad de salto de ruta fue identificada en GitHub Enterprise Server que permitía a un atacante no autenticado eliminar archivos y directorios arbitrarios en la instancia, incluyendo el directorio completo de almacenamiento de usuario que contenía objetos Git LFS, activos de lanzamiento, adjuntos y avatares. El encabezado de solicitud X-GitHub-Request-Id fue utilizado sin sanitización como un segmento de ruta del sistema de archivos para el directorio de búfer de carga, por lo que un valor de salto apuntaba el búfer a una ruta arbitraria y la rutina de limpieza diferida eliminaba recursivamente el objetivo recorrido. La explotación requería solo accesibilidad de red a la instancia y ninguna autenticación, y funcionaba incluso cuando el modo privado estaba habilitado. Esta vulnerabilidad afectó a todas las versiones de GitHub Enterprise Server anteriores a la 3.22 y fue corregida en las versiones 3.21.4, 3.20.6, 3.19.10, 3.18.13 y 3.17.19. Esta vulnerabilidad fue reportada a través del programa GitHub Bug Bounty."
    }
  ],
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  "metrics": {
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          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
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    "cvssMetricV31": [
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}