CVE-2026-73422 - Astro: Reflected XSS via unescaped View Transition animation properties
Brief
CVE ID : CVE-2026-73422
Published : Aug. 12, 2026, 8:32 p. m.
- 32 minutes ago
Description : Astro is a web framework for content-driven websites. From 2.
- 0 until 7.
- 0, Astro's server-side View Transition CSS generator interpolates animation properties into an inline style element without escaping them for CSS and HTML contexts. An attacker-controlled View Transition animation value such as duration can terminate the generated style element and inject arbitrary HTML or JavaScript.
The affected code is packages/astro/src/runtime/server/transition. ts; renderTransition passes sheet. toString() into markHTMLString(), while addAnimationProperty serializes duration through toTimeValue() and also handles easing, direction, delay, fillMode, and name.