CVE-2026-50146: Astro is a web framework

Routine

HIGH 7.1UPGRADE

CVE-2026-50146 is a high-severity flaw (CVSS 7.1) affecting astro. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

High severity
Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	7.1 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.3% (top 81%)
CISA exploited list	No
Weakness	CWE-80
Published	2026-06-22
Last modified	2026-10-25

Publisher (CNA): GitHub, Inc. · Vendor: astro

Last updated 2026-10-25 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-06-22 19:17 UTCPublished CVE record published
2026-10-25 23:10 UTCUpdated Record last modified

astro astro UPGRADE

Affected: < 6.3.3

Fixed in: 6.3.3

Safe to downgrade to: no unaffected older release

1. Check installed version

npm ls astro

2. UPGRADE to 6.3.3

npm install astro@">=6.3.3"

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-50146?

astro: upgrade to 6.3.3. Exact commands for each OS are on this page.

Is CVE-2026-50146 being exploited?

CVE-2026-50146 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-50146 affect?

CVE-2026-50146 affects astro. Severity is high (CVSS 7.1). 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 attribu

How urgent is CVE-2026-50146?

Priority 35/100. High severity; Public exploit reference

Related CVEs

CVE-2026-54299 HIGH 7.5 UPGRADE Astro is a web framework
CVE-2026-54298 MEDIUM 4.2 UPGRADE Astro is a web framework

References

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