# CVE-2025-64764: Astro is vulnerable to Reflected XSS via the server islands feature

> Attackers can execute arbitrary scripts in user browsers via reflected XSS in Astro's server islands feature, requiring the feature to be enabled.

- **Severity:** High 7.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 19 Nov 2025
- **Updated:** 19 Nov 2025
- **Also known as:** GHSA-wrwg-2hg8-v723

## What is CVE-2025-64764?

CVE-2025-64764 is a high-severity cross-site scripting vulnerability in withastro astro, published on 19 Nov 2025. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

Astro is a web framework. Prior to version 5.15.8, a reflected XSS vulnerability is present when the server islands feature is used in the targeted application, regardless of what was intended by the component template(s). This issue has been patched in version 5.15.8.

Weakness: CWE-80 (Improper Neutralization of Script-Related HTML Tags in a Web Page)

## Which versions are affected by CVE-2025-64764?

2 open source packages ship an affected version, including astro. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `astro` | npm | All versions | 5.15.8 |
| `astro` | npm | All versions | 5.15.8 |

Products: Astro Astro.

## How do I fix CVE-2025-64764?

Upgrade astro to 5.15.8 or later.

## Is CVE-2025-64764 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-64764 exists.

Public exploit code:

- Astro - Reflected XSS via server islands feature (nuclei): http/cves/2025/CVE-2025-64764.yaml

## Other vulnerabilities in withastro astro

- [CVE-2024-56159](https://insights.sbomify.com/CVE-2024-56159/): Server source code is exposed to the public if sourcemaps are enabled (high 7.8)
- [CVE-2026-54299](https://insights.sbomify.com/CVE-2026-54299/): Astro: Host header SSRF in prerendered error page fetch (high 7.5)
- [CVE-2025-59837](https://insights.sbomify.com/CVE-2025-59837/): astro allows bypass of image proxy domain validation leading to SSRF and potential XSS (high 7.2)
- [CVE-2026-50146](https://insights.sbomify.com/CVE-2026-50146/): Astro: Reflected XSS via unescaped slot name (high 7.1)
- [CVE-2025-64765](https://insights.sbomify.com/CVE-2025-64765/): Astro middleware authentication checks based on url.pathname can be bypassed via url encoded values (medium 6.9)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-64764 and fix it if it is affected.

What it is: CVE-2025-64764 is a high-severity cross-site scripting vulnerability in withastro astro, published on 19 Nov 2025. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-64764 exists.

Affected packages and fixed versions:
- astro (npm): affected all versions; fixed in 5.15.8
- astro (npm): affected all versions; fixed in 5.15.8

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-64764/ (Markdown: https://insights.sbomify.com/CVE-2025-64764/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-64764
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-64764
- OSV: https://osv.dev/vulnerability/CVE-2025-64764

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-64764/
Summaries are generated and may contain mistakes; the official description above is the record.