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Improper Handling of URL Encoding (Hex Encoding) in hono

CVE-2026-29045

  • hono
Severity High
Score 9.8/10

Summary

Hono is a Web application framework that provides support for any JavaScript runtime. Prior to version 4.12.4, when using serveStatic together with route-based middleware protections (e.g. app.use('/admin/*', ...)), inconsistent URL decoding allowed protected static resources to be accessed without authorization. The router used decodeURI, while serveStatic used decodeURIComponent. This mismatch allowed paths containing encoded slashes (%2F) to bypass middleware protections while still resolving to the intended filesystem path. This issue has been patched in version 4.12.4.

  • LOW
  • NETWORK
  • HIGH
  • UNCHANGED
  • NONE
  • NONE
  • HIGH
  • HIGH

CWE-177 - Improper Handling of URL Encoding (Hex Encoding)

The software does not properly handle when all or part of an input has been URL encoded.

Advisory Timeline

  • Published