Slackware has issued an advisory on August 6: http://www.slackware.com/security/viewer.php?l=slackware-security&y=2016&m=slackware-security.535426 You can see the issue was fixed in the upstream changelog in 5.34: https://www.stunnel.org/sdf_ChangeLog.html Mageia 5 may also be affected.
Cauldron now has latest upstream version. Mageia 5 has still version 5.03, whereas the fix appears in 5.34 only, I don't think backporting the correction is worth the trouble.
Status: NEW => RESOLVEDResolution: (none) => FIXED