CVE-2026-61456
Grav before 1.0.3 Stored XSS via SVG Upload API
- State
- Published
- Severity
- 5.1 Medium
- Published
- Jul 10, 2026
- Updated
- Jul 10, 2026
- Reserved
- Jul 9, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 5.1 Medium | 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 | VulnCheck |
| 3.1 | 4.6 Medium | CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N | VulnCheck |
Weaknesses
- CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Affected Products
| Product | Versions |
|---|---|
gravgetgrav |
|
References
- GitHub Security Advisory (GHSA-7vhm-8x52-2r5p)vendor-advisory
- VulnCheck Advisory: Grav before 1.0.3 Stored XSS via SVG Upload APIthird-party-advisory
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