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VULNERABILITIES

CVE-2026-86252 Details

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.

Metrics

CVSS 3.x Severity and Vector Strings:

CNA: [email protected]CVSS-B:5.3 MEDIUMVector:CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

References to Advisories, Solutions, and Tools

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URLSource(s)Tag(s)
https://github.com/h3js/h3/security/advisories/GHSA-4hxc-9384-m385 CISA-ADP
https://github.com/h3js/h3/security/advisories/GHSA-4hxc-9384-m385 [email protected]
https://www.vulncheck.com/advisories/h3-before-1.15.9-sse-event-injection-via-carriage-return [email protected]

Weakness Enumeration

CWE-IDCWE NameSource
CWE-74Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')[email protected]

Affected Products

No affected product data is available for this CVE.

Change History

2 change records found show changes

QUICK INFO

CVE Dictionary Entry:
CVE-2026-86252
NVD Published Date:
Sep 6, 2026
NVD Last Modified:
Sep 8, 2026
Source:
[email protected]