PoC Index

CVE-2026-33128

CRITICAL 10.0EPSS 0.6%

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.

CVSS v3.1
10.0 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
CVSS v3.1
7.5 HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:H/A:N
CVSS v3.1
7.5 HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:H/A:N
EPSS
0.57% chance of exploitation in the next 30 days, 45th percentile
Published
2026-03-20

Proof-of-concept exploits (1)

References

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