Description
Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.13.16, mount() and app.mount() can remove a dynamic mount prefix using the route-pattern length rather than the matched-prefix length, allowing a crafted path to be forwarded as a protected inner route while the outer application routes the original path. Since 4.12.21, rebuilding the forwarded URL from the decoded pathname can also convert a decoded backslash to a slash and collapse parent-directory segments, again causing the mounted application to receive a protected path. An unauthenticated client can use either applicable path transformation to reach a mounted route without authentication or authorization middleware scoped to a subpath inside the mount prefix. This issue is fixed in version 4.13.16.
Published: 2026-11-12
Score: 5.3 Medium
EPSS: < 1% Very Low
KEV: No
AI Analysis

Analysis and contextual insights are available on OpenCVE Cloud.

Remediation

No vendor fix or workaround currently provided.

Additional remediation guidance may be available on OpenCVE Cloud.

Tracking

Sign in to view the affected projects.

Advisories
Source ID Title
Github GHSA Github GHSA GHSA-4m76-xfj5-7975 Hono: `mount()` and `app.mount()` can forward a path that bypasses middleware scoped inside the mount prefix
History

Sat, 14 Nov 2026 05:00:00 +0000

Type Values Removed Values Added
First Time appeared Hono
Hono hono
Vendors & Products Hono
Hono hono

Thu, 12 Nov 2026 22:30:00 +0000

Type Values Removed Values Added
Description Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.13.16, mount() and app.mount() can remove a dynamic mount prefix using the route-pattern length rather than the matched-prefix length, allowing a crafted path to be forwarded as a protected inner route while the outer application routes the original path. Since 4.12.21, rebuilding the forwarded URL from the decoded pathname can also convert a decoded backslash to a slash and collapse parent-directory segments, again causing the mounted application to receive a protected path. An unauthenticated client can use either applicable path transformation to reach a mounted route without authentication or authorization middleware scoped to a subpath inside the mount prefix. This issue is fixed in version 4.13.16.
Title Hono: `mount()` and `app.mount()` can forward a path that bypasses middleware scoped inside the mount prefix
Weaknesses CWE-288
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: 2026-11-12T22:18:46.437Z

Reserved: 2026-11-10T21:12:01.227Z

Link: CVE-2026-126357

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Deferred

Published: 2026-11-13T00:20:10.873

Modified: 2026-11-13T00:20:11.013

Link: CVE-2026-126357

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-11-14T04:45:19Z

Weaknesses
  • CWE-288

    Authentication Bypass Using an Alternate Path or Channel