CVE-2026-50146

⚠️ high

Summary

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.

CVSS Score

7.1

High

EPSS Score

0.2

Exploit Probability

Published Date

2026-06-22

First Seen: 2026-06-25

📊 Relative Risk Intelligence

This CVE is Moderate Risk - more severe than 53.3% of all 329,456 vulnerabilities in our database.

#153,866

Above average severity

Severity Percentile

🎯 CISA SSVC Assessment Updated: Jun 23, 2026

🔍 Exploitation Status

Poc

Proof-of-concept available

⚙️ Automatable

Requires human interaction

💥 Technical Impact

Partial

Limited system impact

SSVC data provided by CISA

Last Modified 2026-06-23

Source NVD 🔗

CVSS Vector 3.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:H/A:N

CWE IDs (Weakness Types)

CWE-80

📦 Affected Products 1

Vendor	Product	Status	Affected Versions
astro	astro	Affected	< 6.3.3

🔗 References 1

https://github.com/withastro/astro/security/advisori...

Exploit Mitigation Vendor Advisory

🔗 Related CVEs 6

CVE ID	Severity	CVSS	EPSS	Summary	Published
CVE-2026-54298	🔶 medium	4.2	0.2	Astro is a web framework. Prior to 6.4.6, the spreadAttributes function in Astro's server-side rendering pipeline iterat...	2026-06-22
CVE-2026-54299	⚠️ high	7.5	0.2	Astro is a web framework. Prior to 6.4.6, Astro SSR apps with prerendered error pages (/404 or /500 using export const p...	2026-06-22
CVE-2026-45028	🔶 medium	6.1	0.0	Astro is a web framework. Astro versions prior to 6.1.10 used AES-GCM encryption to protect the confidentiality and inte...	2026-05-13
CVE-2026-41067	🔶 medium	6.1	0.0	Astro is a web framework. Prior to 6.1.6, the defineScriptVars function in Astro's server-side rendering pipeline uses a...	2026-04-24
CVE-2026-33769	🔶 medium	5.3	0.0	Astro is a web framework. From version 2.10.10 to before version 5.18.1, this issue concerns Astro's remotePatterns path...	2026-03-24
CVE-2025-66202	🔶 medium	6.5	0.3	Astro is a web framework. Versions 5.15.7 and below have a double URL encoding bypass which allows any unauthenticated a...	2025-12-09

These CVEs affect the same products