CVE-2026-33129: medium-severity vulnerability in h3js h3
h3 has an observable timing discrepancy in basic auth utils
Published
E-mail alert when it lands in KEV, gets a public PoC or its score goes up.
13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 5.9epss 0.3%
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:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Affected products
h3js · h3Related CVEs — h3js h3
In the same product, most dangerous first.
CVE-2026-23527HIGHh3 v1 has Request Smuggling (TE.TE) issueEPSS 0.6%CVE-2026-86253HIGHh3 before 1.15.6 Path Traversal via Percent-Encoded Dot SegmentsEPSS 0.6%CVE-2026-33128HIGHh3 has a Server-Sent Events Injection via Unsanitized Newlines in Event Stream FieldsEPSS 0.6%CVE-2026-86250HIGHh3 before 2.0.1-rc.18 Denial of Service via Unbounded Chunked CookieEPSS 0.5%CVE-2026-86251HIGHh3 before 1.15.9 Path Traversal via Double DecodingEPSS 0.4%CVE-2026-33131HIGHh3 has a middleware bypass with one gadgetEPSS 0.4%