CVE-2026-33128

h3 has a Server-Sent Events Injection via Unsanitized Newlines in Event Stream Fields

CVSS 7.5 HIGHEPSS 0.5%CWE-93

Vexday Risk Score

21Baixo

Decisão SSVC (CISA)

Track

Sem sinal de exploração → monitorar

CVSS 7.5EPSS 0.5%KEV nãoPoC —Nuclei —Metasploit —Patch —

Ciclo de vida

20 mar 2026Publicada no NVD

Recomendação: Monitorar — sem sinal de exploração no momento.

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

Produtos afetados

h3js · h3

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Referências

https://github.com/h3js/h3/blob/52c82e18bb643d124b8b9ec3b1f62b081f044611/src/utils/internal/event-stream.ts#L170-L187 https://github.com/h3js/h3/commit/7791538e15ca22437307c06b78fa155bb73632a6 https://github.com/h3js/h3/security/advisories/GHSA-22cc-p3c6-wpvm