CVE-2026-33129

5.9 MEDIUM 0.3% exploit odds Fix listed Other Server

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.

At a glance

Exploitability: Can be exploited over the network without logging in. High risk of data exposure.
Exploit odds: 0.3% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2026-03-20 10:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-06-17 10:36 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.3% in the next 30 days (EPSS).
Severity: 5.9 MEDIUM (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2026-03-20 10:16 UTC
Last modified: 2026-06-17 10:36 UTC
Exploit probability: 0.3% · EPSS, next 30 days
Weakness: CWE-208
Record status: Analyzed

Affected

h3 2.0.0
h3 2.0.1

Attack profile CVSS 3.1 · 5.9

Attack vector: Network
Complexity: High
Privileges needed: None
User interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: None
Availability: None

Raw vector

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

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-33129.md and follow it. Check whether this project is affected by CVE-2026-33129. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record