CVE-2026-50146: withastro astro · Basic XSS
Affects withastro astroSource CVE Database V5
Not known to be exploited · CVSS 7.1 High : upgrade to 6.3.3 soon.
Data as of 5 Nov 2026, 00:01 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 19% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 6.3.3
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:H/A:NExploitation evidence
Disclosed: evidence found.
CVE published 22 Jun 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 5 Nov 2026.
What to do
Upgrade astro and withastro/astro to 6.3.3.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| withastroastro | Affected
| Fixed in
|
GitHubwithastro/astropkg:github/withastro/astroOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Upgrade to Astro version 6.3.3 or later, where this vulnerability is fixed. No other official remediation or temporary fixes are indicated. Patch status is confirmed by the vendor advisory stating the fix is in 6.3.3.
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.