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TI-2026-29706 Aliases CVE-2026-41067GHSA-j687-52p2-xcff

Astro: XSS via incomplete `</script>` sanitization in `define:vars` allows case-insensitive and whitespace-based bypass

Priority MEDIUM 60CWE-79Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Required
Attack complexity
Low
Impact type
Cross-site scripting
Confidentiality · integrity · availability
Low · Low · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-79.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00189 8th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed astro (withastro): 6.1.6astro (npm): 6.1.6

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
withastroastrobefore 6.1.66.1.6Patch availableCNA
—astro (npm)before 6.1.66.1.6Patch availableGHSA-j687-52p2-xcff
  • astro Vendorwithastro Affected before 6.1.6 Fixed in 6.1.6 Patch available CNA
  • astro (npm) Vendor— Affected before 6.1.6 Fixed in 6.1.6 Patch available GHSA-j687-52p2-xcff

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:astro:astro:*:*:*:*:*:node.js:*:*before 6.1.6Vulnerablewithastro
  • cpe:2.3:a:astro:astro:*:*:*:*:*:node.js:*:* Versions before 6.1.6 Vulnerable ·withastro

Remediation

  • Fix · CNA astro (withastro) Fixed in 6.1.6
  • Fix · GHSA-j687-52p2-xcff astro (npm) Fixed in 6.1.6 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-41067
  2. 2026-10-03 Alias added: GHSA-j687-52p2-xcff

References

Exploit 1

Advisory 1

Other 2

  • TI-2024-37142 Server source code is exposed to the public if sourcemaps are enabled CVSS 4.0HIGH 7.8
  • TI-2025-34958 Unauthorized third-party images in Astro’s _image endpoint CVSS 4.0MEDIUM 6.9
  • TI-2025-39915 Server-side request forgery in withastro astro CVSS 3.1MEDIUM 6.5
  • TI-2025-38274 Astro's `X-Forwarded-Host` is reflected with no validation CVSS 3.1MEDIUM 6.5
  • TI-2026-36915 Astro: Reflected XSS via unescaped slot name CVSS 3.1HIGH 7.1
  • TI-2025-40102 Astro is vulnerable to Reflected XSS via the server islands feature CVSS 3.1HIGH 7.1
See all 19 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences