Stored XSS via unescaped shortcode attributes
Published Aug 19, 2026 · Updated Aug 19, 2026
Stored XSS in Grav Shortcode Core Plugin before 6.2.2 allows remote authenticated users to execute JavaScript via crafted shortcode attributes. Security::detectXss() only blocks content containing a literal less-than sign, so shortcode parameters pass the save-time check, and ColorShortcode.php plus related handlers concatenate attacker input into HTML attributes without output encoding. Reachability requires an account with admin.pages permission and a page view; execution can affect unauthenticated visitors and can act in an administrator session if an administrator opens or previews the stored page.
Summary
What happened
Stored XSS in Grav Shortcode Core Plugin before 6.2.2 allows remote authenticated users to execute JavaScript via crafted shortcode attributes. Security::detectXss() only blocks content containing a literal less-than sign, so shortcode parameters pass the save-time check, and ColorShortcode.php plus related handlers concatenate attacker input into HTML attributes without output encoding. Reachability requires an account with admin.pages permission and a page view; execution can affect unauthenticated visitors and can act in an administrator session if an administrator opens or previews the stored page.
The record
- CVE
- CVE-2026-64851
- Published
- Aug 19, 2026
- Updated
- Aug 19, 2026
- Vendor
- Grav
- Product
- Grav Shortcode Core Plugin
- Classifications
- CWE-79, T1059.007
- 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=< 6.2.2
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-q5fw-vpqc-fgph proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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