GHSA-9hp6-4448-45g2: Hono's flaw in URL path parsing could cause path confusion

Summary

A flaw in the getPath utility function could allow path confusion and potential bypass of proxy-level ACLs (e.g. Nginx location blocks).

Details

The original implementation relied on fixed character offsets when parsing request URLs. Under certain malformed absolute-form Request-URIs, this could lead to incorrect path extraction.

Most standards-compliant runtimes and reverse proxies reject such malformed requests with a 400 Bad Request, so the impact depends on the application and environment.

Impact

If proxy ACLs are used to protect sensitive endpoints such as /admin, this flaw could have allowed unauthorized access. The confidentiality impact depends on what data is exposed: if sensitive administrative data is exposed, the impact may be High (CVSS 7.5); otherwise it may be Medium (CVSS 5.3).

Resolution

The implementation has been updated to correctly locate the first slash after "://", preventing such path confusion.

References

• GHSA-9hp6-4448-45g2
• honojs/hono@1d79aed
• https://github.com/honojs/hono/releases/tag/v4.9.6