fetchmail: Buffer Overflow

Background

fetchmail is a utility that retrieves and forwards mail from remote systems using IMAP, POP, and other protocols.

Description

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.

Impact

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.

Workaround

There are no known workarounds at this time.

Resolution

All fetchmail users should upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose ">=net-mail/fetchmail-6.2.5.2"