Buildkite Elastic CI for AWS time-of-check-time-of-use race condition vulnerability

A time-of-check-time-of-use race condition vulnerability in Buildkite Elastic CI for AWS versions prior to 6.7.1 and 5.22.5 allows the buildkite-agent user to bypass a symbolic link check for the PIPELINEPATH variable in the fix-buildkite-agent-builds-permissions script...