MCollective is a framework to build server orchestration or parallel job execution systems.
A vulnerability was discovered in MCollective which allowed for deserialized YAML from agents without calling safe_load. This allows the potential for arbitrary code execution on the server.
A remote attacker could possibly execute arbitrary code with the privileges of the process or cause a Denial of Service condition.
There is no known workaround at this time.
All MCollective users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=app-admin/mcollective-2.11.0"