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.

CVSS v3 8.9 HIGH

8.9^/10

CVSS v3 : HIGH

Vector :

Exploitability : 2.2 / Impact : 6.0

Attack Vector NETWORK

Attack Complexity HIGH

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact LOW

Scope CHANGED

References

Link	Resource
https://github.com/h3js/h3/commit/618ccf4f37b8b6148bea7f36040471af45bfb097	Patch
https://github.com/h3js/h3/security/advisories/GHSA-mp2g-9vg9-f4cg	Exploit Vendor Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:h3:h3:*:*:*:*:*:node.js:*:*

History

23 Jan 2026, 18:50

Type	Values Removed	Values Added
CPE		cpe:2.3:a:h3:h3::::::node.js::*
References	~~() https://github.com/h3js/h3/commit/618ccf4f37b8b6148bea7f36040471af45bfb097 -~~	() https://github.com/h3js/h3/commit/618ccf4f37b8b6148bea7f36040471af45bfb097 - Patch
References	~~() https://github.com/h3js/h3/security/advisories/GHSA-mp2g-9vg9-f4cg -~~	() https://github.com/h3js/h3/security/advisories/GHSA-mp2g-9vg9-f4cg - Exploit, Vendor Advisory
First Time		H3 h3 H3

15 Jan 2026, 20:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-01-15 20:16

Updated : 2026-01-23 18:50

NVD link : CVE-2026-23527

Mitre link : CVE-2026-23527

CVE.ORG link : CVE-2026-23527

JSON object : View

Products Affected

h3

h3

CWE

CWE-444

Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')

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