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.
Published: 2026-05-28
Score: 5.3 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-2gcr-mfcq-wcc3 Hono: app.mount() strips mount prefix using undecoded path, causing incorrect routing for percent-encoded paths
History

Fri, 29 May 2026 17:00:00 +0000

Type Values Removed Values Added
First Time appeared Hono
Hono hono
CPEs cpe:2.3:a:hono:hono:*:*:*:*:*:node.js:*:*
Vendors & Products Hono
Hono hono

Thu, 28 May 2026 20:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


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: 2026-05-28T19:13:28.934Z

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

Link: CVE-2026-47676

cve-icon Vulnrichment

Updated: 2026-05-28T19:13:22.352Z

cve-icon NVD

Status : Analyzed

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

Modified: 2026-05-29T16:55:56.880

Link: CVE-2026-47676

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-05-30T21:00:12Z

Weaknesses