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CVE PROGRAM SOURCE RECORD6.9 Medium

CVE-2026-86252

h3 before 1.15.9 SSE Event Injection via Carriage Return

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Status
Published
Published
Updated
Assigning organization
VulnCheck

Description

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 products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

h3js h3

Default version status: unaffected

  • 0 to < 1.15.9affected
  • 1.15.9unaffected
  • 2.0.0-beta.0 to < 2.0.1-rc.17affected
  • 2.0.1-rc.17unaffected
pkg:npm/h3

References