CVE-2025-54793
📋 TL;DR
Astro web framework versions 5.2.0 through 5.12.7 contain an open redirect vulnerability in trailing slash redirection logic when handling paths with double slashes. Attackers can craft URLs to redirect users to arbitrary external domains, increasing phishing and social engineering risks. This affects sites using on-demand rendering (SSR) with Node or Cloudflare adapters, but not static sites or sites deployed to Netlify or Vercel.
💻 Affected Systems
- Astro
📦 What is this software?
Astro by Astro
⚠️ Risk & Real-World Impact
Worst Case
Users are redirected to malicious phishing sites that steal credentials, financial information, or install malware, leading to account compromise, data breaches, or ransomware infections.
Likely Case
Attackers use crafted URLs in phishing campaigns to redirect users to fake login pages or malicious sites, potentially harvesting credentials or distributing malware.
If Mitigated
With proper patching or workarounds, the vulnerability is eliminated, preventing any redirect manipulation while maintaining normal site functionality.
🎯 Exploit Status
Exploitation requires no authentication and involves simple URL crafting. The vulnerability is publicly disclosed with technical details available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 5.12.8
Vendor Advisory: https://github.com/withastro/astro/security/advisories/GHSA-cq8c-xv66-36gw
Restart Required: No
Instructions:
1. Update Astro to version 5.12.8 or later using npm: npm update astro@latest. 2. Verify the update completed successfully. 3. Test site functionality to ensure no regression issues.
🔧 Temporary Workarounds
Network-level redirect blocking
allBlock outgoing redirect responses with Location headers starting with '//' at the network level (firewall, WAF, or proxy).
🧯 If You Can't Patch
- Implement network-level blocking of redirects with Location headers starting with '//' using WAF rules or firewall policies.
- Monitor web server logs for suspicious redirect patterns and implement alerting for attempted exploitation.
🔍 How to Verify
Check if Vulnerable:
Check if your Astro version is between 5.2.0 and 5.12.7 and you're using Node.js or Cloudflare adapter with SSR. Test with crafted URL: https://yourdomain.com//external-site.com/ and observe if redirect occurs.Check Version:
npm list astro | grep astroVerify Fix Applied:
After updating to 5.12.8+, test the same crafted URL to confirm no redirect occurs. The request should return a 404 or appropriate error instead of redirecting.📡 Detection & Monitoring
Log Indicators:
- HTTP 301/302 redirect responses with Location headers containing '//' followed by external domains
- Unusual spike in redirect requests to unfamiliar paths
Network Indicators:
- Outbound HTTP redirects to external domains originating from crafted URLs with double slashes
SIEM Query:
http.status_code IN (301, 302) AND http.location STARTSWITH '//'