Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, Ember’s HTTP/1.1 parser accepts differing duplicate Content-Length headers and uses the last value instead of rejecting the message. When an Ember server is behind a keep-alive intermediary that selects a different occurrence, an unauthenticated attacker can create CL.CL request smuggling that bypasses front-end controls, captures a later user’s headers, or poisons a cache. The shared client parser can also misframe responses from a malicious or compromised upstream when the client acts as a proxy for multiple downstream consumers. This issue is fixed in versions 0.23.35 and 1.0.0-M47.
References
Configurations
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History
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Information
Published : 2026-09-15 20:17
Updated : 2026-09-16 14:17
NVD link : CVE-2026-69217
Mitre link : CVE-2026-69217
CVE.ORG link : CVE-2026-69217
JSON object : View
Products Affected
No product.
CWE
CWE-444
Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
