MAVEN · SEPTEMBER 2026 · EARLY WARNING

http4s-ember-core Maven Package Vulnerability: Early Warning

EARLY WARNING · UNCONFIRMED. This page describes a developing threat that 0Day surfaced from early signals and has not yet independently confirmed. Details may change. Always verify against the primary sources before acting.
Severity
HIGH
Affected component
http4s-ember-core_2.12 (maven)
Patched version
Not yet available
GHSA-8H4C-X2WG-6XP8

An early warning has been issued for a vulnerability in the http4s-ember-core Maven package that may enable HTTP request smuggling. Users of this package are advised to assess their exposure and prepare for potential mitigation steps.

What happened

An early warning has been issued regarding a vulnerability in the http4s-ember-core Maven package. The package reportedly does not reject HTTP/1.1 requests that carry both Transfer-Encoding and Content-Length headers. This behavior may enable HTTP request smuggling, which can lead to security bypass, request hijacking, and cache poisoning. The vulnerability is under investigation and no authoritative version range has been published yet.

The affected components include http4s-ember-core_2.12, http4s-ember-core_2.13, and http4s-ember-core_3. Users of these components should review their dependencies and assess their exposure to this vulnerability. The primary source indicates that versions up to 0.23.34 are affected, with a patched version 0.23.35 available.

What to do about it

How 0Day would have caught this

MATCHED TO YOUR ACTUAL DEPENDENCY GRAPH0Day matches every incoming threat signal against your GitHub organization’s full dependency graph, including transitive dependencies. If http4s-ember-core_2.12 is anywhere in your dependency tree, the engineers who own the affected repositories get a push alert the moment it is flagged — no manual audit to remember to run.

Read how this differs from waiting on a scanner to catch a known advisory, or see the exact, read-only access 0Day needs to do this for an organization.

Frequently asked questions

Am I affected?

If you are using http4s-ember-core_2.12, http4s-ember-core_2.13, or http4s-ember-core_3 in your project, you may be affected. Check your dependencies against the affected versions.

What should I do right now?

Monitor the primary sources for updates and prepare to upgrade to the patched version 0.23.35 or apply recommended workarounds as soon as they are available.

Is there an official fix available?

Yes, version 0.23.35 of http4s-ember-core is reported to be patched. Upgrade to this version if you are using an affected version.

Sources

Join the 0Day waitlist →

← Back to all threats