ReDoS in Apache MXNet RTC Module

A regular expression used in Apache MXNet (incubating) is vulnerable to a potential denial-of-service by excessive resource consumption. The bug could be exploited when loading a model in Apache MXNet that has a specially crafted operator name that would cause the regular expression evaluation to use excessive resources to attempt a match. This issue affects Apache MXNet versions prior to 1.9.1.

The clustered setup of Apache MXNet allows users to specify which IP address and port the scheduler will listen on via the DMLC_PS_ROOT_URI and DMLC_PS_ROOT_PORT env variables. In versions older than 1.0.0, however, the MXNet framework will listen on 0.0.0.0 rather than user specified DMLC_PS_ROOT_URI once a scheduler node is initialized. This exposes the instance running MXNet to any attackers reachable via the interface they didn't expect to be listening on. For example: If a user wants to run a clustered setup locally, they may specify to run on 127.0.0.1. But since MXNet will listen on 0.0.0.0, it makes the port accessible on all network interfaces.