cvedb.io
CVE-2026-33490
LOW · CVSS 3.7
EPSS exploitation probability: 0%
Published 2026-03-26T18:16:30.237 · Last modified 2026-06-17T10:37:35.357

Summary

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.

Affected products

h3 — h3

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References

This product uses data from the NVD API but is not endorsed or certified by the NVD. Informational only; not professional security advice.