Hintjens

**Name of the Vulnerable Software and Affected Versions** libzmq versions prior to 4.0.6 libzmq versions 4.1.x prior to 4.1.1 **Description** The issue allows remote attackers to conduct downgrade attacks, bypassing security mechanisms of the ZMTP v3 protocol by using a ZMTP v2 or earlier header. **Recommendations** For libzmq versions prior to 4.0.6, update to version 4.0.6 or later. For libzmq versions 4.1.x prior to 4.1.1, update to version 4.1.1 or later.

**Name of the Vulnerable Software and Affected Versions** libzmq (aka ZeroMQ/C++) version 4.0.5 **Description** The issue allows man-in-the-middle attackers to conduct downgrade attacks via a crafted connection request. **Recommendations** For libzmq (aka ZeroMQ/C++) version 4.0.5, update to a version newer than 4.0.5 to resolve the issue.