withastro up to 4.16.17/5.13.1 Image Optimization Endpoint /_image cross site scripting

Summaryinfo

A vulnerability was found in withastro astro up to 4.16.17/5.13.1. It has been rated as problematic. Affected is an unknown function of the file /_image of the component Image Optimization Endpoint. Performing a manipulation results in cross site scripting. This vulnerability is cataloged as CVE-2025-55303. It is possible to initiate the attack remotely. There is no exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in withastro astro up to 4.16.17/5.13.1. It has been classified as problematic. This affects an unknown function of the file /_image of the component Image Optimization Endpoint. The manipulation with an unknown input leads to a cross site scripting vulnerability. CWE is classifying the issue as 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. This is going to have an impact on integrity. The summary by CVE is:

Astro is a web framework for content-driven websites. In versions of astro before 5.13.2 and 4.16.18, the image optimization endpoint in projects deployed with on-demand rendering allows images from unauthorized third-party domains to be served. On-demand rendered sites built with Astro include an /_image endpoint which returns optimized versions of images. A bug in impacted versions of astro allows an attacker to bypass the third-party domain restrictions by using a protocol-relative URL as the image source, e.g. /_image?href=//example.com/image.png. This vulnerability is fixed in 5.13.2 and 4.16.18.

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2025-55303 since 08/12/2025. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. It demands that the victim is doing some kind of user interaction. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1059.007 for this issue.

Upgrading to version 4.16.18 or 5.13.2 eliminates this vulnerability. Applying the patch 4d16de7f95db5d1ec1ce88610d2a95e606e83820 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2025-25235). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Vendor

• withastro

Name

• astro

Version

• 4.16.0
• 4.16.1
• 4.16.2
• 4.16.3
• 4.16.4
• 4.16.5
• 4.16.6
• 4.16.7
• 4.16.8
• 4.16.9
• 4.16.10
• 4.16.11
• 4.16.12
• 4.16.13
• 4.16.14
• 4.16.15
• 4.16.16
• 4.16.17
• 5.13.0
• 5.13.1

License

• open-source

Website

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

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Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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