Honojs Hono up to 4.13.15 RegExpRouter improper authorization

Summaryinfo

A vulnerability, which was classified as problematic, was found in Honojs Hono up to 4.13.15. The impacted element is an unknown function of the component RegExpRouter. Executing a manipulation can lead to improper authorization. The identification of this vulnerability is CVE-2026-126358. The attack may be launched remotely. There is no exploit available. You should upgrade the affected component.

Detailsinfo

A vulnerability classified as problematic was found in Honojs Hono up to 4.13.15. This vulnerability affects some unknown functionality of the component RegExpRouter. The manipulation with an unknown input leads to a improper authorization vulnerability. The CWE definition for the vulnerability is CWE-285. The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action. As an impact it is known to affect confidentiality. CVE summarizes:

Hono is a Web application framework that provides support for any JavaScript runtime. From 4.1.4 until 4.13.16, RegExpRouter can omit wildcard middleware in three version-specific cases: since 4.13.0, middleware using the explicit default parameter pattern in /api/:tenant{[^/]+}/admin/* is not applied to a route written as /api/:tenant/admin/:id; since 4.1.4, middleware on /admin/* is not applied to a route registered as /admin* for paths under /admin/; and since 4.4.0, a request path containing an encoded line terminator can reach the not-found handler without wildcard middleware. The default SmartRouter selects RegExpRouter for most applications, and the router's registration-time coverage calculation treated the first two matching pattern pairs as different while its compiled wildcard did not match line terminators in the third case. An unauthenticated client can reach a route handler or the not-found handler without authentication or authorization middleware registered on the wildcard path. TrieRouter, LinearRouter, and PatternRouter apply the middleware in the three described cases. This issue is fixed in version 4.13.16.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-126358 since 11/10/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are neither technical details nor an exploit publicly available. The MITRE ATT&CK project declares the attack technique as T1548.002.

Upgrading to version 4.13.16 eliminates this vulnerability.

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Productinfo

Vendor

• Honojs

Name

• Hono

Version

• 4.13.0
• 4.13.1
• 4.13.2
• 4.13.3
• 4.13.4
• 4.13.5
• 4.13.6
• 4.13.7
• 4.13.8
• 4.13.9
• 4.13.10
• 4.13.11
• 4.13.12
• 4.13.13
• 4.13.14
• 4.13.15

Website

• Product: https://github.com/honojs/hono/

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