Cross-site scripting via unescaped spread attribute names
Published Jun 22, 2026 · Updated Jun 22, 2026
Cross-site scripting in Astro before 6.4.6 allows remote attackers to execute JavaScript in users' browsers through crafted spread-prop keys. In server-side rendering, spreadAttributes passes each object key to addAttribute, which inserts the key into HTML without validation or escaping. Exploitation requires an application to spread attacker-controlled object keys onto an HTML element and a user to render the resulting page; the injected script runs in that user's browser context.
Summary
What happened
Cross-site scripting in Astro before 6.4.6 allows remote attackers to execute JavaScript in users' browsers through crafted spread-prop keys. In server-side rendering, spreadAttributes passes each object key to addAttribute, which inserts the key into HTML without validation or escaping. Exploitation requires an application to spread attacker-controlled object keys onto an HTML element and a user to render the resulting page; the injected script runs in that user's browser context.
The record
- CVE
- CVE-2026-54298
- Published
- Jun 22, 2026
- Updated
- Jun 22, 2026
- Vendor
- Astro
- Product
- Astro
- Classifications
- CWE-79, T1189
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jun 22, 2026CVE publishedPublication date reported by the CVE source.
- Jun 22, 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=< 6.4.6
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-jrpj-wcv7-9fh9 SSR spread-prop proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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