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CVE-2026-69217

Http4s: Ember Server accepts duplicate Content-Length headers PUBLISHED

Description (CNA)

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.

Affected (CNA)

Vendor / productVersions
http4s / http4saffected < 0.23.35; affected >= 1.0.0-M1, < 1.0.0-M47

CWE

CWE-444

References

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.