CVE-2026-23527: high-severity vulnerability in h3js h3
h3 v1 has Request Smuggling (TE.TE) issue
Published · Updated
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21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 8.9epss 0.6%
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:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:L
Affected products
h3js · h3Related CVEs — h3js h3
In the same product, most dangerous first.
CVE-2026-86253HIGHh3 before 1.15.6 Path Traversal via Percent-Encoded Dot SegmentsEPSS 0.6%CVE-2026-33128HIGHh3 has a Server-Sent Events Injection via Unsanitized Newlines in Event Stream FieldsEPSS 0.6%CVE-2026-86250HIGHh3 before 2.0.1-rc.18 Denial of Service via Unbounded Chunked CookieEPSS 0.5%CVE-2026-86251HIGHh3 before 1.15.9 Path Traversal via Double DecodingEPSS 0.4%CVE-2026-33131HIGHh3 has a middleware bypass with one gadgetEPSS 0.4%CVE-2026-86252MEDIUMh3 before 1.15.9 SSE Event Injection via Carriage ReturnEPSS 0.4%