Is CVE-2025-64764 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2025-64764 being exploited in the wild.

How severe is CVE-2025-64764?

High severity, with a CVSS score of 7.1, published 19 November 2025.

Which products and versions are affected?

astro (npm) SEMVER:introduced=0,fixed=5.15.8.

Is there a fix for CVE-2025-64764?

Yes. astro (npm): upgrade to 5.15.8 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2025-64764 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2025-64764?

Check whether you run Astro or astro (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2025-64764: Astro reflected XSS via server islands feature

CVE-2025-64764 · Severity: high · CVSS 7.1 · Published 2025-11-19

Astro is a web framework used to build fast, content-focused websites. The server islands feature allows dynamic server-rendered components, but contains an XSS vulnerability that allows attackers to inject malicious scripts through URL parameters. An attacker can craft a special URL that, when clicked by a user, executes arbitrary JavaScript in the victim's browser, potentially stealing session cookies, credentials, or performing actions on behalf of the user.

Technologies: Astro, astro (npm). Vendors: Astro, npm.

Quick answers

Is CVE-2025-64764 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2025-64764 being exploited in the wild.
How severe is CVE-2025-64764?: High severity, with a CVSS score of 7.1, published 19 November 2025.
Which products and versions are affected?: astro (npm) SEMVER:introduced=0,fixed=5.15.8.
Is there a fix for CVE-2025-64764?: Yes. astro (npm): upgrade to 5.15.8 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2025-64764 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2025-64764?: Check whether you run Astro or astro (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

astro (npm): upgrade to 5.15.8 or later
```
npm install astro@5.15.8
```

Technical details

The vulnerability is a reflected cross-site scripting (XSS) flaw in Astro's server islands feature. The `/_server-islands/[name]` endpoint accepts three parameters: `e` (component export), `p` (properties), and `s` (slots). When the `e` parameter is set to "file", the endpoint generates an HTML template using the island's absolute file path as an HTML tag name and injects the `s` parameter value directly as child content using `markHTMLString` without proper sanitization. This allows an unauthenticated attacker to inject arbitrary HTML/JavaScript via the `s` parameter in a URL. The attack requires user interaction (clicking a malicious link) but works regardless of the actual component template design. The vulnerability affects all versions up to 5.15.6 and is patched in version 5.15.8.

Affected products

Astro Astro <= 5.15.6

Identifiers

CVE-2025-64764
GHSA-wrwg-2hg8-v723

Timeline

2025-11-19: disclosed
2025-11-19: patched: Fixed in version 5.15.8

References

https://github.com/withastro/astro/security/advisories/GHSA-wrwg-2hg8-v723

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