CVE-2026-50146

FAUCET Score

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.

First published: Jun 22, 2026Last modified: Jun 22, 2026

Impacted Technologies

Vendor	Product	Version(s)	CPE
		< 6.3.3CPE matchmatch criteria	cpe:2.3:a:astro:astro::::::node.js::*

CVSS Data

CVSS version used by this source: 3.1

7.1HIGH

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 Impact

LOW

Integrity Impact

HIGH

Availability Impact

NONE

Exploitability Score

2.8

Impact Score

4.2

CvssVersion

3.1

Exploit Intelligence

EPSS Score

0.27%

Probability of exploitation in next 30 days

EPSS Percentile

18.8%

Percentile rank of EPSS score among Peer Group

As of 2026-07-28

Model: v2026.06.15

This CVE's current EPSS score of 0.0027 is in the 19th percentile among its peer group of 26,236 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.1 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (2)

npmpatch availablevia ghsa

Product: astroFixed in: 6.3.3

github_advisoryworkaround availablevia nvd_reference

View patch

Vendor Advisories (1)

npmGHSA-8hv8-536x-4wqphigh

Astro: Reflected XSS via unescaped slot name

Jun 16, 2026

References

github.com / withastro/astro/security/advisories/GHSA-8hv8-536x-4wqp

ExploitMitigationVendor Advisory