High severity7.1GHSA Advisory· Published Jun 22, 2026· Updated Jun 23, 2026

CVE-2026-50146

Description

Astro is a web framework. Prior to 6.3.3, when a component uses a client:* directive, Astro inserts named slot content into a data-astro-template attribute without HTML escaping the slot name allowing an attacker to break out of the attribute context and inject arbitrary HTML, resulting in reflected XSS during SSR. This vulnerability is fixed in 6.3.3.

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LLM-synthesized narrative grounded in this CVE's description and references.

Affected packages

Versions sourced from the GitHub Security Advisory.

Package	Affected versions	Patched versions
astronpm	< 6.3.3	6.3.3

Affected products

Withastro/Astro2 versions
cpe:2.3:a:astro:astro:*:*:*:*:*:node.js:*:*+ 1 more
- cpe:2.3:a:astro:astro:*:*:*:*:*:node.js:*:*range: <6.3.3
- (no CPE)range: < 6.3.3
ghsa-coords
pkg:npm/astro
Range: < 6.3.3

Patches

Vulnerability mechanics

References

github.com/withastro/astro/security/advisories/GHSA-8hv8-536x-4wqpnvdExploitMitigationVendor AdvisoryWEB
github.com/advisories/GHSA-8hv8-536x-4wqpghsaADVISORY
nvd.nist.gov/vuln/detail/CVE-2026-50146ghsaADVISORY

News mentions

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cvss	0.461
epss	0.000
exploit	0.000
kev	0.000
patch	0.000
ransomware	0.000