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Vulnerabilities / CVE-2026-69204

critical

CVE-2026-69204

Http4s Ember accepts Transfer-Encoding combined with Content-Length (CL.TE request smuggling)

Published Modified CWE 444
In the Trivy database since at least 24 Oct 2026, 07:11 UTCWhen it arrived before that build is not recorded.

Severity by source

GHSA9.2CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N

Trivy's own label is CRITICAL. Rated critical by GHSA.

Description

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 and fixed versions

SourcePackageFixed in
maven::GitHub Security Advisory Mavenorg.http4s:http4s-ember-core_2.12, org.http4s:http4s-ember-core_2.13, org.http4s:http4s-ember-core_30.23.35 and 1 more
Show all 3 entries from 1 source
SourcePackageFixed in
maven::GitHub Security Advisory Mavenorg.http4s:http4s-ember-core_2.120.23.35
maven::GitHub Security Advisory Mavenorg.http4s:http4s-ember-core_2.130.23.35, 1.0.0-M47
maven::GitHub Security Advisory Mavenorg.http4s:http4s-ember-core_30.23.35, 1.0.0-M47

References

Vulnerability data compiled from the Trivy vulnerability database (trivy-db, Aqua Security, Apache License 2.0), which aggregates third-party advisories. CVE records are published by The MITRE Corporation under the CVE Terms of Use; CVE is a trademark of MITRE. This product uses data from the NVD API but is not endorsed or certified by the NVD. Severity, titles and advisory data from the GitHub Advisory Database (CC BY 4.0), Red Hat security data (CC BY 4.0) and the other sources linked on each entry. Entries may be summarised or re-formatted; the linked original is the authoritative record.