CVE-2026-33769 Astro: Remote allowlist bypass via unanchored matchPathname wildcard
Attackers can bypass remote URL allowlists to access unintended internal paths via unanchored wildcard matching in Astro's image optimization endpoint.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-33769?
CVE-2026-33769 is a low-severity server-side request forgery vulnerability in withastro astro, published on 24 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Astro is a web framework. From version 2.10.10 to before version 5.18.1, this issue concerns Astro's remotePatterns path enforcement for remote URLs used by server-side fetchers such as the image optimization endpoint. The path matching logic for /* wildcards is unanchored, so a pathname that contains the allowed prefix later in the path can still match. As a result, an attacker can fetch paths outside the intended allowlisted prefix on an otherwise allowed host. This issue has been patched in version 5.18.1.
Weakness: CWE-20
Which versions are affected by CVE-2026-33769?
2 open source packages ship an affected version, including astro. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
astro npm | From 2.10.10 | 5.18.1 |
astro npm | From 2.10.10 | 5.18.1 |
Products include Astro Astro.
How do I fix CVE-2026-33769?
Upgrade astro to 5.18.1 or later.
Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.
Is CVE-2026-33769 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-33769 exists.
Other vulnerabilities in withastro astro
- CVE-2024-56159 Server source code is exposed to the public if sourcemaps are enabled
- CVE-2026-54299 Astro: Host header SSRF in prerendered error page fetch
- CVE-2025-59837 astro allows bypass of image proxy domain validation leading to SSRF and potential XSS
- CVE-2026-50146 Astro: Reflected XSS via unescaped slot name
- CVE-2025-64764 Astro is vulnerable to Reflected XSS via the server islands feature
Sources
Also known as GHSA-g735-7g2w-hh3f.