Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.12.21, app.mount() strips the mount prefix from the incoming request path using the raw URL pathname, while route matching is performed against the percent-decoded path. This inconsistency causes the prefix to be stripped at the wrong position when the path contains percent-encoded multi-byte characters, resulting in the mounted sub-application receiving an incorrect path. This vulnerability is fixed in 4.12.21.
History

Thu, 28 May 2026 17:00:00 +0000

Type Values Removed Values Added
Description Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.12.21, app.mount() strips the mount prefix from the incoming request path using the raw URL pathname, while route matching is performed against the percent-decoded path. This inconsistency causes the prefix to be stripped at the wrong position when the path contains percent-encoded multi-byte characters, resulting in the mounted sub-application receiving an incorrect path. This vulnerability is fixed in 4.12.21.
Title Hono: app.mount() strips mount prefix using undecoded path, causing incorrect routing for percent-encoded paths
Weaknesses CWE-444
CWE-693
References
Metrics cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-05-28T15:26:01.672Z

Reserved: 2026-05-19T21:10:38.798Z

Link: CVE-2026-47676

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-05-28T17:16:32.697

Modified: 2026-05-28T17:16:32.697

Link: CVE-2026-47676

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.