h3js h3 up to 2.0.0-0/2.0.1-rc.16/2.0.2-rc.17 mount name resolution

Summaryinfo

A vulnerability was found in h3js h3 up to 2.0.0-0/2.0.1-rc.16/2.0.2-rc.17 and classified as problematic. This vulnerability affects the function mount. Executing a manipulation can lead to name resolution. This vulnerability is handled as CVE-2026-33490. The attack can be executed remotely. There is not any exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability has been found in h3js h3 up to 2.0.0-0/2.0.1-rc.16/2.0.2-rc.17 and classified as problematic. This vulnerability affects the function mount. The manipulation with an unknown input leads to a name resolution vulnerability. The CWE definition for the vulnerability is CWE-706. The product uses a name or reference to access a resource, but the name/reference resolves to a resource that is outside of the intended control sphere. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

H3 is a minimal H(TTP) framework. In versions 2.0.0-0 through 2.0.1-rc.16, the `mount()` method in h3 uses a simple `startsWith()` check to determine whether incoming requests fall under a mounted sub-application's path prefix. Because this check does not verify a path segment boundary (i.e., that the next character after the base is `/` or end-of-string), middleware registered on a mount like `/admin` will also execute for unrelated routes such as `/admin-public`, `/administrator`, or `/adminstuff`. This allows an attacker to trigger context-setting middleware on paths it was never intended to cover, potentially polluting request context with unintended privilege flags. Version 2.0.2-rc.17 contains a patch.

The advisory is available at github.com. This vulnerability was named CVE-2026-33490 since 03/20/2026. The exploitation appears to be difficult. The attack can be initiated remotely. The exploitation needs additional levels of successful authentication. Technical details are known, but there is no available exploit.

Upgrading to version 2.0.1-rc.17 eliminates this vulnerability.

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Productinfo

Vendor

• h3js

Name

• h3

Version

• 2.0
• 2.0.1-rc.0
• 2.0.1-rc.1
• 2.0.1-rc.2
• 2.0.1-rc.3
• 2.0.1-rc.4
• 2.0.1-rc.5
• 2.0.1-rc.6
• 2.0.1-rc.7
• 2.0.1-rc.8
• 2.0.1-rc.9
• 2.0.1-rc.10
• 2.0.1-rc.11
• 2.0.1-rc.12
• 2.0.1-rc.13
• 2.0.1-rc.14
• 2.0.1-rc.15
• 2.0.1-rc.16
• 2.0.2-rc.0
• 2.0.2-rc.1
• 2.0.2-rc.2
• 2.0.2-rc.3
• 2.0.2-rc.4
• 2.0.2-rc.5
• 2.0.2-rc.6
• 2.0.2-rc.7
• 2.0.2-rc.8
• 2.0.2-rc.9
• 2.0.2-rc.10
• 2.0.2-rc.11
• 2.0.2-rc.12
• 2.0.2-rc.13
• 2.0.2-rc.14
• 2.0.2-rc.15
• 2.0.2-rc.16
• 2.0.2-rc.17

Website

• Product: https://github.com/h3js/h3/

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