Zeromq · Zeromq · CVE-2020-15166
**Name of the Vulnerable Software and Affected Versions**
ZeroMQ versions prior to 4.3.3
**Description**
The issue is related to an error in the resource control mechanism of ZeroMQ, a messaging system component. This allows a remote attacker to cause a denial-of-service. Users with TCP transport public endpoints, even with CURVE/ZAP enabled, are impacted. If a raw TCP socket is opened and connected to an endpoint that is fully configured with CURVE/ZAP, legitimate clients will not be able to exchange any messages. Handshakes complete successfully, and messages are delivered to the library, but the server application never receives them.
**Recommendations**
For ZeroMQ versions prior to 4.3.3, update to version 4.3.3 to resolve the issue. As a temporary workaround, consider restricting access to TCP transport public endpoints to minimize the risk of exploitation. Avoid using raw TCP sockets connected to endpoints fully configured with CURVE/ZAP until the issue is resolved.