Description
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.
CVSS Metrics
- Vector
- CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
- Attack Vector
- network
- Complexity
- high
- Privileges
- none
- User Action
- none
- Scope
- unchanged
- Confidentiality
- none
- Integrity
- low
- Availability
- none
- Weaknesses
- CWE-706
Metadata
- Primary Vendor
- H3
- Published
- 3/26/2026
- Last Modified
- 3/31/2026
- Source
- NIST NVD
- Note: Verify all details with official vendor sources before applying patches.
Affected Products
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