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: n/a
KEV: No
Impact: n/a
Action: n/a
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History

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'}

Subscriptions

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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

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cve-icon NVD

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cve-icon Redhat

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cve-icon OpenCVE Enrichment

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Weaknesses
  • CWE-288

    Authentication Bypass Using an Alternate Path or Channel