CVE-2026-50146
Astro: Reflected XSS via unescaped slot name
CVSS Score
7.1
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-80 |
| Vendor | withastro |
| Product | astro |
| Published | Jun 22, 2026 |
Stay Ahead of the Next One
Get instant alerts for withastro astro
Be the first to know when new high vulnerabilities affecting withastro astro are published — delivered to Slack, Telegram or Discord.
Get Free Alerts →
Free · No credit card · 60 sec setup
CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:H/A:N Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
Low
Integrity
High
Availability
None
Affected Versions
withastro / astro
< 6.3.3