Is CVE-2026-33490 actively exploited?

No active exploitation of CVE-2026-33490 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2026-33490 be exploited remotely?

Yes. CVE-2026-33490 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2026-33490?

CVE-2026-33490 has a CVSS score of 5.3 (MEDIUM).

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MEDIUM

CVE-2026-33490

CWE-706Published: March 26, 2026· Updated: Mar 31, 2026

5.3

CVSS v3.1

EPSS:0.03%probability of exploitation in 30 daysPercentile:8.1th

Official 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.

NVD Source

Technical Analysis

CVE-2026-33490 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.