Astro development server error page is vulnerable to reflected Cross-site Scripting

Description

A Reflected Cross-Site Scripting (XSS) vulnerability exists in Astro’s development server error pages when the trailingSlash configuration option is used. An attacker can inject arbitrary JavaScript code that executes in the victim’s browser context by crafting a malicious URL.

Recommendation

Update the astro package to the latest compatible version. Followings are version details:

• Affected version(s): >= 5.2.0, < 5.15.6
• Patched version(s): 5.15.6

References

• GHSA-w2vj-39qv-7vh7
• CVE-2025-64745
• CWE-79
• CAPEC-310
• OWASP 2021-A3
• OWASP 2021-A6

Related Issues

• Elysia vulnerable to prototype pollution with multiple standalone schema validation - CVE-2025-66456
• Astro Cloudflare adapter has Stored Cross-site Scripting vulnerability in /_image endpoint - CVE-2025-65019
• Astro's middleware authentication checks based on url.pathname can be bypassed via url encoded values - CVE-2025-64765
• Astro allows unauthorized third-party images in _image endpoint - CVE-2025-55303

Tags:

npm

astro