withastro Astro up to 7.4.4 Dynamic-Tag Renderer/JSX Renderer/MDX Renderer injection

Summaryinfo

A vulnerability classified as critical was found in withastro Astro up to 7.4.4. This affects an unknown function of the component Dynamic-Tag Renderer/JSX Renderer/MDX Renderer. Executing a manipulation can lead to injection. This vulnerability is handled as CVE-2026-126361. The attack can be executed remotely. There is not any exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability has been found in withastro Astro up to 7.4.4 and classified as critical. This vulnerability affects an unknown function of the component Dynamic-Tag Renderer/JSX Renderer/MDX Renderer. The manipulation with an unknown input leads to a injection vulnerability. The CWE definition for the vulnerability is CWE-74. The product constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

Astro is a web framework for content-driven websites. Prior to 7.4.5, Astro rendered a string used as a dynamic element name as raw HTML after applying an incomplete character filter. A / in the string could make an HTML parser treat the remainder as attributes, allowing untrusted element-name input to inject event-handler markup. The .astro dynamic-tag renderer, JSX renderer, and MDX renderer were affected, and exploitation required an application to use request-controlled or stored untrusted data as all or part of an element name. This issue is fixed in version 7.4.5.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-126361 since 11/10/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are neither technical details nor an exploit publicly available. The MITRE ATT&CK project declares the attack technique as T1055.

Upgrading to version 7.4.5 eliminates this vulnerability.

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Productinfo

Vendor

• withastro

Name

• Astro

Version

• 7.4.0
• 7.4.1
• 7.4.2
• 7.4.3
• 7.4.4

Website

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

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