Hono contains a flaw in URL path parsing, potentially leading to path confusion

Vulnerability Description

Hono is a Web application framework that provides support for any JavaScript runtime. Versions 4.8.0 through 4.9.5 contain a flaw in the getPath utility function which could allow path confusion and potential bypass of proxy-level ACLs (e.g. Nginx location blocks). 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 depending on the application and environment. 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, otherwise it may be moderate. This issue is fixed in version 4.9.6.

References

• https://github.com/honojs/hono/security/advisories/GHSA-9hp6-4448-45g2
• https://github.com/honojs/hono/commit/1d79aedc3f82d8c9969b115fe61bc4bd705ec8de
• https://github.com/honojs/hono/releases/tag/v4.9.6