CVE-2026-33129CWE-208

h3 has an observable timing discrepancy in basic auth utils

Medium · published March 20, 2026

CVSS v3.1
5.9
EPSS
0%
Percentile
39.1
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
5.9 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
CVSS v4.0
Not supplied
EPSS
0.00462 · 39.1th percentile
Weakness
CWE-208 · Observable Timing Discrepancy
Published
2026-03-20T09:41Z
EPSS history
Timeline
  • 20 MAR 09:41Z
    h3 has an observable timing discrepancy in basic auth utils
    cvelistv5