CVE-2026-54298: Astro XSS via unescaped attribute names in spread properties

CVE-2026-54298 · Severity: medium · CVSS 4.2 · Published 2026-06-22

Astro is a web framework used to build and render websites. A security flaw in how it handles component properties allows attackers to inject malicious code into web pages if the site uses data from untrusted sources like web addresses or external databases. If exploited, this could allow an attacker to steal user session information, deface the website, or trick users into providing sensitive credentials.

Technologies: astro (npm). Vendors: npm.

Quick answers

Is CVE-2026-54298 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-54298 being exploited in the wild.
How severe is CVE-2026-54298?
Medium severity, with a CVSS score of 4.2, published 22 June 2026.
Which products and versions are affected?
astro (npm) < 6.4.6, SEMVER:introduced=0,fixed=6.4.6.
Is there a fix for CVE-2026-54298?
Yes. astro (npm): upgrade to 6.4.6 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-54298 attacked?
It is attacked over the network, in a software library.
Am I affected by CVE-2026-54298?
Check whether you run 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 6.4.6 or later
    npm install astro@6.4.6

Technical details

A Cross-Site Scripting (XSS) vulnerability exists in Astro's server-side rendering pipeline within the spreadAttributes function. The root cause is that while attribute values are escaped, the attribute keys (names) are interpolated directly into the HTML output without sanitization or escaping. An attacker can provide a malicious object where the keys contain double quotes and JavaScript event handlers (e.g., 'onmousemove'). When these keys are processed via the spread syntax {...props} on an HTML element, they break out of the attribute context to execute arbitrary JavaScript. This affects both SSR and static builds if the data source is untrusted. The issue is resolved in version 6.4.6.

Affected products

  • withastro Astro < 6.4.6

Identifiers

  • CVE-2026-54298
  • GHSA-jrpj-wcv7-9fh9

Timeline

  • 2026-06-12: advisory: GitHub Security Advisory published
  • 2026-06-22: disclosed: NVD publication date
  • 2026-06-22: patched: Fix confirmed in version 6.4.6

References

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