Withastro Astro up to 7.3.2 View Transition CSS Generator injection

Summaryinfo

A vulnerability was found in Withastro Astro up to 7.3.2. It has been declared as critical. Affected by this issue is some unknown functionality of the component View Transition CSS Generator. The manipulation results in injection. This vulnerability is known as CVE-2026-114127. It is possible to launch the attack remotely. No exploit is available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, was found in Withastro Astro up to 7.3.2. Affected is some unknown processing of the component View Transition CSS Generator. The manipulation with an unknown input leads to a injection vulnerability. CWE is classifying the issue as 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. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

Astro is a web framework for content-driven websites. From 7.1.0 until 7.3.3, Astro's server-side View Transition CSS generator does not keep string animation properties within their generated declarations. An application that passes attacker-controlled data into properties such as duration, delay, easing, direction, fillMode, or animation names can allow CSS delimiters to terminate the declaration and add attacker-selected rules to the server-rendered page. The generated stylesheet still escapes literal less-than characters, so the injected content cannot terminate the style element or directly inject HTML or JavaScript. The injected CSS can conceal or reposition content, add generated text, and otherwise misrepresent the interface; some applications may also expose data already present in selectable DOM attributes through conditional resource loads. This issue is fixed in 7.3.3.

The advisory is shared for download at github.com. This vulnerability is traded as CVE-2026-114127 since 10/20/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. There are neither technical details nor an exploit publicly available. The MITRE ATT&CK project declares the attack technique as T1055.

Upgrading to version 7.3.3 eliminates this vulnerability.

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Productinfo

Vendor

• Withastro

Name

• Astro

Version

• 7.3.0
• 7.3.1
• 7.3.2

Website

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

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