Vulnerability · Published Sep 2, 2026 · Assigned by GitHub_M

CVE-2026-84376Astro: Authorization bypass from missing path-segment boundary check when stripping the configured base

Medium 6.3

In plain English

A medium-severity security flaw in astro from withastro. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 54% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)6.3Medium

Exploit odds (30 days)0.7%top 46.4% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

Astro is a web framework for content-driven websites. Prior to 7.2.4, Astro stripped a configured non-root base path from request pathnames using a string-prefix check without verifying a path-segment boundary. With base "/app", a request to "/appX/admin" resolved internally to the protected "/admin" route while middleware observed "/appX/admin" in context.url.pathname. In applications that authorize base-prefixed routes by inspecting context.url.pathname, an unauthenticated remote attacker could bypass pathname-based middleware authorization and reach protected routes. This issue is fixed in version 7.2.4.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
npm	astro	7.2.4	GHSA-376h-93r7-7g6f

Affected products (as reported)

Vendor	Product	Versions
withastro	astro	< 7.2.4

Weakness: CWE-187 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N

References

https://github.com/withastro/astro/security/advisories/GHSA-376h-93r7-7g6f x_refsource_CONFIRM
https://github.com/withastro/astro/pull/17701 x_refsource_MISC
https://github.com/withastro/astro/commit/05763a0884aabb1da78a2749d5bb9d41ae620527 x_refsource_MISC
https://github.com/withastro/astro/releases/tag/astro@7.2.4 x_refsource_MISC