Publisher-level stored XSS via unquoted event attributes
Published May 11, 2026 · Updated May 11, 2026
Stored XSS in Grav before 2.0.0-beta.2 allows remote authenticated users with publisher access to execute JavaScript in visitors' browsers. Security::detectXss() uses an on_events blacklist regex that requires a quoted or whitespace-delimited value after '=', so unquoted event-handler attributes evade the check. Publisher-level page-edit access is required; a saved payload runs in the Grav site origin when affected content is rendered, exposing visitor data and actions to the injected script.
Summary
What happened
Stored XSS in Grav before 2.0.0-beta.2 allows remote authenticated users with publisher access to execute JavaScript in visitors' browsers. Security::detectXss() uses an on_events blacklist regex that requires a quoted or whitespace-delimited value after '=', so unquoted event-handler attributes evade the check. Publisher-level page-edit access is required; a saved payload runs in the Grav site origin when affected content is rendered, exposing visitor data and actions to the injected script.
The record
- CVE
- CVE-2026-42612
- Published
- May 11, 2026
- Updated
- May 11, 2026
- Vendor
- Grav
- Product
- Grav
- Classifications
- CWE-79, T1203
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- May 11, 2026CVE publishedPublication date reported by the CVE source.
- May 11, 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=< 2.0.0-beta.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
- GHSA unquoted event-attribute filter bypassproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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