Detections
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CVE-2026-23527
critical
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.
References
https://simonkoeck.com/writeups/h3-transfer-encoding-request-smuggling
https://github.com/h3js/h3/security/advisories/GHSA-mp2g-9vg9-f4cg
https://github.com/h3js/h3/releases/tag/v1.15.5
https://github.com/h3js/h3/commit/618ccf4f37b8b6148bea7f36040471af45bfb097