CVE-2026-54299: withastro astro · Improper Input Validation
Affects withastro astroSource CVE Database V5
Not known to be exploited · CVSS 7.5 High : upgrade to 6.4.6 soon.
Data as of 5 Nov 2026, 00:01 UTC
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 26% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 6.4.6
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:L/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 withastro astro to 6.4.6.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| withastroastro | Affected
| Fixed in
|
AI-suggested
Upgrade Astro to version 6.4.6 or later, where this vulnerability is fixed by validating the Host header against allowedDomains before using it to construct fetch URLs. Until upgrading, ensure that the Host header is properly validated or restricted to trusted domains to prevent exploitation.
Description
Astro is a web framework. Prior to 6.4.6, Astro SSR apps with prerendered error pages (/404 or /500 using export const prerender = true) fetch those pages over HTTP at runtime when an error occurs. The URL for this fetch is derived from request.url, which in turn gets its origin from the incoming Host header. When the Host header is not validated against allowedDomains, an attacker can point the fetch at an arbitrary host and read the response. This vulnerability is fixed in 6.4.6.