What’s Vulnerable › Vulnerabilities

CVE-2025-64745: Astro development server error page vulnerable to reflected Cross-site Scripting

• Severity: medium (CVSS 6.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2025-11-13 · updated 2026-10-18
• Weakness: CWE-79

Description

Astro is a web framework. Starting in version 5.2.0 and prior to version 5.15.6, 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. While this vulnerability only affects the development server and not production builds, it could be exploited to compromise developer environments through social engineering or malicious links. Version 5.15.6 fixes the issue.

Affected products

• withastro astro: from 5.2.0 before 5.15.6 — fixed in 5.15.6

How to fix

Upgrade to a fixed version: withastro astro 5.15.6. Check the vendor advisory for mitigations.

References

• https://github.com/withastro/astro/blob/5bc37fd5cade62f753aef66efdf40f982379029a/packages/astro/src/template/4xx.ts#L133-L149
• https://github.com/withastro/astro/commit/790d9425f39bbbb462f1c27615781cd965009f91
• https://github.com/withastro/astro/pull/12994
• https://github.com/withastro/astro/security/advisories/GHSA-w2vj-39qv-7vh7

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