Vulnerability · Published Mar 24, 2026 · Assigned by GitHub_M

CVE-2026-33769Astro: Remote allowlist bypass via unanchored matchPathname wildcard

Low 2.9

In plain English

A low-severity improper input validation in astro from withastro. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 27% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)2.9Low

Exploit odds (30 days)0.3%top 72.7% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
npm	astro	5.18.1	GHSA-g735-7g2w-hh3f

Affected products (as reported)

Vendor	Product	Versions
withastro	astro	>= 2.10.10, < 5.18.1

Weakness: CWE-20 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:P

References

https://github.com/withastro/astro/security/advisories/GHSA-g735-7g2w-hh3f x_refsource_CONFIRM