fetchmail is a utility that retrieves and forwards mail from remote systems using IMAP, POP, and other protocols.
fetchmail does not properly validate UIDs coming from a POP3 mail server. The UID is placed in a fixed length buffer on the stack, which can be overflown.
Very long UIDs returned from a malicious or compromised POP3 server can cause fetchmail to crash, resulting in a Denial of Service, or allow arbitrary code to be placed on the stack.
There are no known workarounds at this time.
All fetchmail users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=net-mail/fetchmail-6.2.5.2"