CVE-2026-54298
Astro: XSS via Unescaped Attribute Names in Spread Props
MEDIUM 6.1EPSS 0.2%
Astro is a web framework. Prior to 6.4.6, the spreadAttributes function in Astro's server-side rendering pipeline iterates over object keys and passes them directly to addAttribute, which interpolates the key into the HTML output without escaping. When a developer uses the spread syntax {...props} on an HTML element and the object keys come from an untrusted source (API, CMS, URL parameters), an attacker can inject arbitrary HTML attributes including event handlers like onmousemove, onclick, or break out of the attribute context entirely to inject new elements. This vulnerability is fixed in 6.4.6.
- Affected
- withastro · astro
- CVSS v3.1 NVD
- 6.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - CVSS v3.1 GITHUB
- 4.2 MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N - EPSS
- 0.23% chance of exploitation in the next 30 days, 13th percentile
- Published
- 2026-06-22
- Updated
- 2026-06-23