CVE-2025-59837
📋 TL;DR
This vulnerability in Astro's image proxy allows attackers to bypass domain validation by using backslashes in the href parameter, enabling server-side requests to arbitrary URLs. This can lead to SSRF attacks and potentially XSS. Affects Astro versions 5.13.4 through 5.13.9.
💻 Affected Systems
- Astro
📦 What is this software?
Astro by Astro
⚠️ Risk & Real-World Impact
Worst Case
Full server compromise through SSRF to internal services, data exfiltration, or XSS leading to account takeover.
Likely Case
SSRF attacks to internal services, port scanning, or XSS payload delivery to users.
If Mitigated
Limited impact if network segmentation restricts internal service access and input validation is in place.
🎯 Exploit Status
Simple parameter manipulation required; advisory includes technical details.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 5.13.10
Vendor Advisory: https://github.com/withastro/astro/security/advisories/GHSA-qcpr-679q-rhm2
Restart Required: Yes
Instructions:
1. Update Astro to version 5.13.10 or later. 2. Run 'npm update @astrojs/astro' or equivalent package manager command. 3. Restart the Astro application.
🔧 Temporary Workarounds
Disable image proxy
allTemporarily disable Astro's image proxy feature if not required.
Modify Astro configuration to remove or disable image proxy settings
Input validation filter
allAdd middleware to filter backslashes in href parameters before processing.
Implement request filtering in your Astro middleware or server configuration
🧯 If You Can't Patch
- Implement network segmentation to restrict outbound connections from the Astro server
- Deploy a WAF with SSRF protection rules to block malicious requests
🔍 How to Verify
Check if Vulnerable:
Check if Astro version is between 5.13.4 and 5.13.9 and image proxy is enabled.Check Version:
npm list @astrojs/astro | grep @astrojs/astroVerify Fix Applied:
Confirm Astro version is 5.13.10 or later and test image proxy functionality.📡 Detection & Monitoring
Log Indicators:
- Unusual outbound requests from Astro server
- Requests with backslashes in URL parameters
Network Indicators:
- Unexpected connections from Astro server to internal/external services
SIEM Query:
source="astro" AND (url="*\\*" OR dest_ip!="expected_domains")