Arbitrary Code Execution Vulnerability in RequestStore Rack (CVE-2017-1234)

Summary

RequestStore provides per-request global storage for Rack. The files published as part of request_store 1.3.2 have 0666 permissions, meaning that they are world-writable, which allows local users to execute arbitrary code. This version was published in 2017, and most production environments do not allow access for local users, so the chances of this being exploited are very low, given that the vast majority of users will have upgraded, and those that have not, if any, are not likely to be exposed.