CVE-2026-33129 MEDIUM

CVE-2026-33129: h3 has an observable timing discrepancy in basic auth utils

Vendor H3Js
Product h3
Weakness CWE-208
Published March 20, 2026
Last update March 20, 2026
View on NVD All CVEs

CVSS base score

5.9/10
Attack vector Network
Attack complexity High
Privileges required None
User interaction None
Confidentiality High
Integrity None

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

What the vulnerability does

01Description

H3 is a minimal H(TTP) framework. Versions 2.0.1-beta.0 through 2.0.0-rc.8 contain a Timing Side-Channel vulnerability in the requireBasicAuth function due to the use of unsafe string comparison (!==). This allows an attacker to deduce the valid password character-by-character by measuring the server's response time, effectively bypassing password complexity protections. This issue is fixed in version 2.0.1-rc.9.

Key dates

02Disclosure timeline

March 20, 2026 CVE published
March 20, 2026 Record updated