A AegiFlow
CRITICALCVSS 9.2EPSS 0.3%

CVE-2026-69204

CVE-2026-69204 updated by NVD

Published
2026-09-15
Modified
2026-09-18
EPSS percentile
26%
Sources
github-advisory, nvd

Summary

Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, Ember HTTP/1.1 does not reject messages containing both Transfer-Encoding and Content-Length, so an intermediary and Ember can select different body framing rules. When ember-server is behind a keep-alive intermediary that forwards both headers and frames by Content-Length, an unauthenticated attacker can smuggle a second request, bypass intermediary access controls, poison caches, or cause a victim request to be joined to an attacker-controlled prefix. The shared response parser can also desynchronize an ember-client connection when a malicious or compromised upstream sends both headers. This issue is fixed in versions 0.23.35 and 1.0.0-M47.

Affected packages

EcosystemPackageAffected versionsFixed versions
Mavenorg.http4s:http4s-ember-core_2.120.23.35
Mavenorg.http4s:http4s-ember-core_2.130.23.35, 1.0.0-M47
Mavenorg.http4s:http4s-ember-core_30.23.35, 1.0.0-M47

Remediation: Upgrade to 0.23.35 or later.

References

Includes data from the GitHub Advisory Database, licensed under CC-BY 4.0.

Includes data from the National Vulnerability Database (NIST). NVD data is in the public domain; this page is not endorsed by NIST.

CVE® is a registered trademark of The MITRE Corporation. CVE content reproduced under the CVE Terms of Use; copyright designation © MITRE.

EPSS scores provided by the FIRST.org Exploit Prediction Scoring System.