CVE-2026-33129 — MEDIUM (5.9)

Vulnerability Description

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.

CVSS Score

5.9

MEDIUM

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

Attack Vector

NETWORK

Attack Complexity

HIGH

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality

HIGH

Integrity

NONE

Availability

NONE

Affected Products

Vendor	Product	Versions
H3	H3	2.0.0

Related Weaknesses (CWE)

CWE-208

References

https://github.com/h3js/h3/pull/1283Issue Tracking
https://github.com/h3js/h3/releases/tag/v2.0.1-rc.9Patch
https://github.com/h3js/h3/security/advisories/GHSA-26f5-8h2x-34xhExploitVendor Advisory

FAQ

What is CVE-2026-33129?

CVE-2026-33129 is a vulnerability with a CVSS score of 5.9 (MEDIUM). 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 (!==)...

How severe is CVE-2026-33129?

CVE-2026-33129 has been rated MEDIUM with a CVSS base score of 5.9/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-33129?

Check the references section above for vendor advisories and patch information. Affected products include: H3 H3.