Hono: `serveStatic` decodes the request path a second time, leading to bypass of middleware on static paths

Why it is Yellow

• CVSS 5.3 medium
• On your watchlist: npm

Affected packages

References

• https://github.com/advisories/GHSA-5r4p-p66f-jhc7
• https://github.com/honojs/hono/security/advisories/GHSA-5r4p-p66f-jhc7
• https://nvd.nist.gov/vuln/detail/CVE-2026-111757
• https://github.com/honojs/hono/commit/8b05c774ef1555c70f5ba5e2991b7e77cc3635cc
• https://github.com/honojs/hono/releases/tag/v4.13.11
• https://github.com/advisories/GHSA-5r4p-p66f-jhc7

Original description

Hono is a Web application framework that provides support for any JavaScript runtime. From 4.12.4 until 4.13.11, serveStatic can interpret a malformed percent-encoded path differently from upstream routing middleware and bypass protection for a static prefix. The root cause is serveStatic decodes a routed request path a second time before filesystem lookup. The attack mechanism is malformed percent encoding survives the first routing interpretation and becomes a protected path only during the later static-file decode. The affected component is serveStatic. The trigger conditions are an application protects a static prefix with upstream middleware and serveStatic receives an attacker-controlled malformed percent-encoded path. The impact is unauthorized disclosure of a static file that upstream middleware was intended to protect. The issue does not permit traversal outside the configured static root. This issue is fixed in version 4.13.11.