CVE-2026-23527

h3: h3: HTTP Request Smuggling due to improper case-sensitive parsing of Transfer-Encoding header

Published 15 Jan 2026Modified 17 Jun 2026CWE 444

In the Trivy database since at least 24 Oct 2026, 07:11 UTCWhen it arrived before that build is not recorded.

Severity by source

NVD9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

GHSA8.9CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:L

Red Hat8.9CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:L

Trivy's own label is CRITICAL. Rated critical by NVD. Rated lower by GHSA (high), Red Hat (high).

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.

Affected packages and fixed versions

Source	Package	Fixed in
npm::GitHub Security Advisory npm	h3	1.15.5

References

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