Astro is a web framework. Prior to 6.1.6, the defineScriptVars function in Astro's server-side rendering pipeline uses a case-sensitive regex /<\/script>/g to sanitize values injected into inline <script> tags via the define:vars directive. HTML parsers close <script> elements case-insensitively and also accept whitespace or / before the closing >, allowing an attacker to bypass the sanitization with payloads like </Script>, </script >, or </script/> and inject arbitrary HTML/JavaScript. This vulnerability is fixed in 6.1.6.

Project Subscriptions

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-j687-52p2-xcff Astro: XSS in define:vars via incomplete </script> tag sanitization
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Fri, 24 Apr 2026 19:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Fri, 24 Apr 2026 17:15:00 +0000

Type Values Removed Values Added
Description Astro is a web framework. Prior to 6.1.6, the defineScriptVars function in Astro's server-side rendering pipeline uses a case-sensitive regex /<\/script>/g to sanitize values injected into inline <script> tags via the define:vars directive. HTML parsers close <script> elements case-insensitively and also accept whitespace or / before the closing >, allowing an attacker to bypass the sanitization with payloads like </Script>, </script >, or </script/> and inject arbitrary HTML/JavaScript. This vulnerability is fixed in 6.1.6.
Title Astro: XSS via incomplete `</script>` sanitization in `define:vars` allows case-insensitive and whitespace-based bypass
Weaknesses CWE-79
References
Metrics cvssV3_1

{'score': 6.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-04-24T18:16:55.536Z

Reserved: 2026-04-16T16:43:03.174Z

Link: CVE-2026-41067

cve-icon Vulnrichment

Updated: 2026-04-24T17:30:46.335Z

cve-icon NVD

Status : Undergoing Analysis

Published: 2026-04-24T17:16:21.083

Modified: 2026-04-24T19:17:11.157

Link: CVE-2026-41067

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

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Weaknesses