Vulnerability in astro (CVE-2026-54299)
Summary
Vulnerability in astro (CVE-2026-54299). Confidential information can be exposed externally. Exploitable via request.url. Mitigation: upgrade to 6.4.6 or later.
Original description
The description as published by the source.
Summary
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.
Who is affected
This affects SSR deployments that:
- Have a prerendered 404 or 500 page
- Use
createRequestFromNodeRequestfromastro/app/nodewithapp.render()without overridingprerenderedErrorPageFetch— this includes custom servers built on the public API and third-party adapters
Not affected:
@astrojs/node>= 9.5.4 (reads error pages from disk)@astrojs/cloudflare(uses the ASSETS binding)- The dev server (renders error pages in-process)
How it works
createRequestFromNodeRequest builds request.url from the raw Host / :authority header. The allowedDomains option is accepted but only gates X-Forwarded-For — it does not constrain the URL origin. (The public createRequest does fall back to localhost for unvalidated hosts; this internal builder did not.)
When app.render() encounters a 404 or 500 with a prerendered error route, default-handler.ts constructs the error page URL using the origin from request.url and fetches it via prerenderedErrorPageFetch, which defaults to global fetch.…
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-54299 has been found in astro.
Attackers can target a specific entry point like request.url over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 7.5/10.
What to do: upgrade astro to 6.4.6 or later.
If unsure, ask your IT team or search "astro CVE-2026-54299" on the vendor's site.
CVE-2026-54299 (astro) — CWE-20 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: request.url / Host / allowedDomains / createRequestFromNodeRequest
Patched: 6.4.6 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-20) exists in astro. Attackers reach the vulnerable code path via request.url without authentication.
Check the vendor advisory for the affected versions of astro. Attack surface: request.url / Host / allowedDomains / createRequestFromNodeRequest.
Severity: High (CVSS 7.5/10). Confidential information can be exposed externally.
Update to 6.4.6.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'astro' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'astro' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
astroを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade astro to 6.4.6ステージング環境で 6.4.6 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
References
- advisory nvd.nist.gov
- package github.com
- web github.com
- web github.com