No. Junglewise Threat Intelligence has no report of CVE-2012-2139 being exploited in the wild.
How severe is CVE-2012-2139?
Informational severity, published 24 October 2017.
Which products and versions are affected?
mail (RubyGems) ECOSYSTEM:introduced=0,fixed=2.4.4.
Is there a fix for CVE-2012-2139?
Yes. mail (RubyGems): upgrade to 2.4.4 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
Am I affected by CVE-2012-2139?
Check whether you run mail (RubyGems) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
How to fix
mail (RubyGems): upgrade to 2.4.4 or later
bundle update mail
Affected products
mail (RubyGems) ECOSYSTEM:introduced=0,fixed=2.4.4