Vulnerability Description
Astro is a web framework for content-driven websites. From 2.9.0 until 7.1.0, 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. Exploitation requires an on-demand or server-rendered route to pass attacker-controlled data into a View Transition animation definition and can execute arbitrary JavaScript in the affected application's origin, allowing access to sensitive page data and authenticated actions available to the victim. This issue is fixed in version 7.1.0.
Related Weaknesses (CWE)
References
- https://github.com/withastro/astro/commit/092da560eea77ee63a3e2c583c80d8238544e4
- https://github.com/withastro/astro/pull/17393
- https://github.com/withastro/astro/releases/tag/[email protected]
- https://github.com/withastro/astro/security/advisories/GHSA-4g3v-8h47-v7g6
- https://github.com/withastro/astro/security/advisories/GHSA-4g3v-8h47-v7g6
FAQ
What is CVE-2026-73422?
CVE-2026-73422 is a documented vulnerability. Astro is a web framework for content-driven websites. From 2.9.0 until 7.1.0, Astro's server-side View Transition CSS generator interpolates animation properties into an inline style element without e...
How severe is CVE-2026-73422?
CVSS scoring is not yet available for CVE-2026-73422. Check NVD for updates.
Is there a patch for CVE-2026-73422?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.