Fetchmail versions 6.3.10 and below suffer from an improper SSL certificate subject verification vulnerability.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/80090/fetchmail-SA-2009-01.txt
Source: https://packetstormsecurity.com/files/80090/Fetchmail-Improper-SSL-Certificate-Verification.html