CVE-2026-23527

8.9 HIGH
Published: January 15, 2026 Modified: January 23, 2026
View on NVD

Description

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.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:L

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://github.com/h3js/h3/security/advisories/GHSA-mp2g-9vg9-f4cg
Source: security-advisories@github.com
Exploit Vendor Advisory

2 reference(s) from NVD

Quick Stats

CVSS v3 Score
8.9 / 10.0
EPSS (Exploit Probability)
0.0%
9th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

h3