User Impersonation Affecting h3 package, versions >=2.0.0-beta.0 <2.0.1-rc.15
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- published19 Mar 2026
- disclosed18 Mar 2026
- credithibwyli
Introduced: 18 Mar 2026
NewCVE-2026-33131 (opens in a new tab)Common Vulnerabilities and Exposures (CVE) are common identifiers for publicly known security vulnerabilities
Common Weakness Enumeration (CWE) is a category system for software weaknesses
How to fix?
Upgrade h3 to version 2.0.1-rc.15 or higher.
Overview
h3 is a Minimal H(TTP) framework built for high performance and portability.
Affected versions of this package are vulnerable to User Impersonation via manipulation of the Host header in HTTP requests, which allows untrusted input to influence the construction of the event.url object. An attacker can bypass middleware protections by crafting requests that spoof the URL, causing the middleware to be bypassed and unauthorized access to protected endpoints.