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Advisories

Grav before 1.0.3 Stored XSS via SVG Upload API

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severity
medium
date
Affecting

  • grav >= 0, < 1.0.3

CWE
  • CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVSS
5.1
CVSS V4 Vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
Credit
alienkeric
Description
The Grav API plugin (getgrav/grav-plugin-api) before 1.0.3 fails to sanitize SVG files uploaded through the POST /api/v1/media endpoint. The HandlesMediaUploads::processUploadedFile() method validates only the file extension and never invokes Security::sanitizeSVG(), so an authenticated attacker with the api.media.write permission can upload an SVG containing arbitrary JavaScript. The file is stored unmodified and served with Content-Type: image/svg+xml; when an administrator opens it in a browser (directly or via <object>/<iframe>), the embedded script executes in their session context, enabling cookie theft and session hijacking.

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