HTTP Request Smuggling Affecting org.http4s:http4s-blaze-server_2.13 package, versions [,0.23.18)[1.0.0-M2,1.0.0-M42)
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- published26 Jul 2026
- disclosed24 Jul 2026
- creditERobertGII
Introduced: 24 Jul 2026
New CVE NOT AVAILABLE CWE-444 (opens in a new tab)How to fix?
Upgrade org.http4s:http4s-blaze-server_2.13 to version 0.23.18, 1.0.0-M42 or higher.
Overview
Affected versions of this package are vulnerable to HTTP Request Smuggling via the Java HTTP parser process. An attacker can bypass access controls, poison backend response queues, or manipulate cache contents by sending specially crafted HTTP/1.1 requests that exploit discrepancies in request boundary parsing between the server and an intermediary. This is only exploitable if a fronting proxy or intermediary interprets HTTP request boundaries differently than the backend parser.
Workaround
This vulnerability can be mitigated by deploying behind an RFC-strict reverse proxy (such as nginx, HAProxy, Envoy, or ALB) that rejects or re-serializes malformed requests at the edge.