Stored XSS via unsanitized SVG upload
Published Aug 19, 2026 · Updated Aug 19, 2026
Stored XSS in Grav API Plugin before 1.0.2 allows remote authenticated users to run script in a browser via uploaded SVG files. HandlesMediaUploads::processUploadedFile() in the POST /api/v1/media path checks only the filename extension and writes the SVG to disk without calling Security::sanitizeSVG(), so embedded script is preserved and later served as image/svg+xml. Exploitation requires api.media.write permission and a user to open the stored SVG; the disclosed impact is browser-session theft and authenticated actions in that user's context.
Summary
What happened
Stored XSS in Grav API Plugin before 1.0.2 allows remote authenticated users to run script in a browser via uploaded SVG files. HandlesMediaUploads::processUploadedFile() in the POST /api/v1/media path checks only the filename extension and writes the SVG to disk without calling Security::sanitizeSVG(), so embedded script is preserved and later served as image/svg+xml. Exploitation requires api.media.write permission and a user to open the stored SVG; the disclosed impact is browser-session theft and authenticated actions in that user's context.
The record
- CVE
- CVE-2026-61607
- Published
- Aug 19, 2026
- Updated
- Aug 19, 2026
- Vendor
- Grav
- Product
- Grav API Plugin
- Classifications
- CWE-79, T1539
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Aug 19, 2026CVE publishedPublication date reported by the CVE source.
- Aug 19, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 1.0.2
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- GitHub advisory proof of concept for SVG upload XSSproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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