XSS in Astro
CVE-2026-41067
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.
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.003 (17.8th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 18th percentile — 17.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.001
Affected products
- Astro
- Withastro Astro — versions < 6.1.6
Weakness classification (CWE)
References
- github.com/withastro/astro/security/advisories/GHSA-j687-52p2-xcff (Exploit, Mitigation, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-41067?
- CVE-2026-41067 is a medium-severity vulnerability in Astro, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-04-24.
- How severe is CVE-2026-41067?
- Medium severity. CVSS v3 base score is 6.1 out of 10.