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CVE-2026-86252

h3 before 1.15.9 SSE Event Injection via Carriage Return PUBLISHED

Description (CNA)

h3 versions before 1.15.9 fail to sanitize carriage return characters in EventStream data and comment fields, allowing attackers to inject arbitrary SSE events by including unsanitized carriage returns. Attackers can inject event type directives, split single push calls into multiple browser-parsed events, or escape comment fields to inject data, bypassing the prior CVE fix that only addressed newline injection.

Affected (CNA)

Vendor / productVersions
h3js / h3affected 0 before 1.15.9; unaffected 1.15.9; affected 2.0.0-beta.0 before 2.0.1-rc.17; unaffected 2.0.1-rc.17

CWE

CWE-74

References

ADP enrichment

CISA-ADP

No English description supplied.