CVE-2026-23527 | THREATINT

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.

PUBLISHED Reserved 2026-01-13 | Published 2026-01-15 | Updated 2026-01-15 | Assigner GitHub_M

HIGH: 8.9CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:L

Problem types

CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')

Product status

< 1.15.5

affected

References

github.com/h3js/h3/security/advisories/GHSA-mp2g-9vg9-f4cg

github.com/...ommit/618ccf4f37b8b6148bea7f36040471af45bfb097

cve.org (CVE-2026-23527)

nvd.nist.gov (CVE-2026-23527)

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