CyberRota Analysis
AI-GeneratedEmber's chunk decoder in Http4s versions prior to 0.23.35 and 1.0.0-M47 is vulnerable to request smuggling due to improper handling of chunk-size tokens, allowing unauthenticated attackers to bypass intermediary controls, poison caches, or hijack request queues. Additionally, this leniency can facilitate response smuggling when the ember-client acts as a gateway to a compromised upstream. Organizations using affected versions should prioritize upgrading to the patched releases to mitigate these risks.
Public Exploit Signal
A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.
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Original NVD Description
Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, Ember’s chunk decoder trims the chunk-size token and accepts leading plus or minus signs instead of requiring one or more hexadecimal digits followed by the required CRLF. When an intermediary forwards chunked data without re-encoding and interprets malformed chunk boundaries differently, an unauthenticated attacker can create TE.TE request smuggling that bypasses intermediary controls, poisons caches, or hijacks the request queue. The same response-path leniency can enable response smuggling against an ember-client used as a gateway when the upstream is malicious or compromised. This issue is fixed in versions 0.23.35 and 1.0.0-M47.