CVE-2026-23527 HIGH

CVE-2026-23527: h3 v1 has Request Smuggling (TE.TE) issue

Vendor H3Js
Product h3
Weakness CWE-444
Published January 15, 2026
Last update April 13, 2026

CVSS base score

8.9/10
Attack vector Network
Attack complexity High
Privileges required None
User interaction None
Confidentiality High
Integrity High

CVSS vector

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

What the vulnerability does

01Description

H3 is a minimal H(TTP) framework built for high performance and portability. Prior to 1.15.5, there is a critical HTTP Request Smuggling vulnerability. readRawBody is doing a strict case-sensitive check for the Transfer-Encoding header. It explicitly looks for "chunked", but per the RFC, this header should be case-insensitive. This vulnerability is fixed in 1.15.5.

Key dates

02Disclosure timeline

January 15, 2026 CVE published
April 13, 2026 Record updated