Vulnerability Report

CVE-2026-23527

Title: HTTP Request Smuggling in H3

Other

Proof Of Concept

No public PoC currently indexed for CVE-2026-23527.

CWE Category CWE-444
Published Date Jan 15, 2026
Modified Date Apr 13, 2026
Exploit Status Not Found
Score 8.9 CVSS v3.1
Exploit Probability (EPSS)
0.58%

Vulnerability Summary

CVE-2026-23527: 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.

Impacted Vendors

A
allwinner 1
H
h3 1

Reference Links

https://github.com/h3js/h3/commit/618ccf4f37b8b6148bea7f36040471af45bfb097 https://github.com/h3js/h3/security/advisories/GHSA-mp2g-9vg9-f4cg
CVSS v3.1
Source Entity [email protected]
Severity HIGH
8.9
Attack Vector
NETWORK
Complexity
HIGH
Privileges
N/A
Interaction
NONE
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
CHANGED
RAW VECTOR CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:L
CVSS v3.1
Source Entity [email protected]
Severity CRITICAL
9.8
Attack Vector
NETWORK
Complexity
LOW
Privileges
N/A
Interaction
NONE
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
UNCHANGED
RAW VECTOR CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Associated Attack Patterns (CAPEC)

Total: Patterns

CVE-2026-23527 Exploits & PoCs (Proof Of Concept)

No public PoCs found in our database for this CVE.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data updated via NVD.

Attack Vector Matrix

Access Vector NETWORK
Complexity HIGH
Privileges N/A
Interaction NONE
CVSS Vector String CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:L

Affected Stack

No specific products linked.