Withastro Astro up to 7.1.1 Solid Renderer cross site scripting

Summaryinfo

A vulnerability marked as problematic has been reported in Withastro Astro up to 7.1.1. Impacted is an unknown function of the component Solid Renderer. This manipulation causes cross site scripting. This vulnerability appears as CVE-2026-126363. The attack may be initiated remotely. There is no available exploit. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability classified as problematic was found in Withastro Astro up to 7.1.1. Affected by this vulnerability is an unknown code of the component Solid Renderer. The manipulation with an unknown input leads to a cross site scripting vulnerability. The CWE definition for the vulnerability is CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. As an impact it is known to affect integrity. The summary by CVE is:

Astro is a web framework for content-driven websites. From 0.2.0 until 7.1.2, the @astrojs/solid-js renderer inserted a named slot into the quoted name attribute of an astro-slot wrapper without HTML escaping. A request-controlled slot name containing a quote could terminate the attribute and inject active HTML. Exploitation required a hydrated Solid component using a client:* directive and dynamic access to the attacker-chosen slot property; a component that did not render that slot emitted only escaped fallback content. This issue is fixed in version 7.1.2.

The advisory is shared at github.com. This vulnerability is known as CVE-2026-126363 since 11/10/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. It demands that the victim is doing some kind of user interaction. Neither technical details nor an exploit are publicly available. MITRE ATT&CK project uses the attack technique T1059.007 for this issue.

Upgrading to version 7.1.2 eliminates this vulnerability.

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Productinfo

Vendor

• Withastro

Name

• Astro

Version

• 7.1.0
• 7.1.1

Website

• Product: https://github.com/withastro/astro/

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