CVE-2026-33490

Описание

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.

A flaw was found in H3, a minimal HTTP framework. The mount() method, responsible for routing requests to sub-applications, incorrectly uses a simple string comparison to check path prefixes. This allows a remote attacker to craft a URL that bypasses the intended path segment boundary. Consequently, middleware designed for specific administrative paths could be triggered for unrelated public paths, potentially leading to the exposure of sensitive information or unintended access due to incorrect privilege flags being set in the request context.