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.
Published: 2026-06-22
Score: 7.1 High
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-8hv8-536x-4wqp Astro: Reflected XSS via unescaped slot name
History

Tue, 23 Jun 2026 14:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

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


Mon, 22 Jun 2026 21:30:00 +0000

Type Values Removed Values Added
First Time appeared Withastro
Withastro astro
Vendors & Products Withastro
Withastro astro

Mon, 22 Jun 2026 18:45:00 +0000

Type Values Removed Values Added
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.
Title Astro: Reflected XSS via unescaped slot name
Weaknesses CWE-80
References
Metrics cvssV3_1

{'score': 7.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:H/A:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-06-23T14:11:04.510Z

Reserved: 2026-06-03T18:49:32.276Z

Link: CVE-2026-50146

cve-icon Vulnrichment

Updated: 2026-06-23T14:10:51.229Z

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-06-22T21:15:04Z

Weaknesses