When the patch was released last year, Exim urged its users to update to the latest version. NSA adds its encouragement to immediately patch to mitigate against this still current threat.
1. Apply Exim Updates Immediately
Update Exim immediately by installing version 4.93 or newer to mitigate this and other vulnerabilities. Other vulnerabilities exist and are likely to be exploited, so the latest fully patched version should be used Using a previous version of Exim leaves a system vulnerable to exploitation. System administrators should continually check software versions and update as new versions become available .