Detections
Analytics
CVE-2026-33128
critical
Description
H3 is a minimal H(TTP) framework. In versions prior to 1.15.6 and between 2.0.0 through 2.0.1-rc.14, createEventStream is vulnerable to Server-Sent Events (SSE) injection due to missing newline sanitization in formatEventStreamMessage() and formatEventStreamComment(). An attacker who controls any part of an SSE message field (id, event, data, or comment) can inject arbitrary SSE events to connected clients. This issue is fixed in versions 1.15.6 and 2.0.1-rc.15.
References
https://github.com/h3js/h3/security/advisories/GHSA-22cc-p3c6-wpvm
https://github.com/h3js/h3/commit/7791538e15ca22437307c06b78fa155bb73632a6