Balsa is a highly configurable email client for GNOME.
Evil Ninja Squirrel discovered a stack-based buffer overflow in the ir_fetch_seq() function when receiving a long response to a FETCH command (CVE-2007-5007).
A remote attacker could entice a user to connect to a malicious or compromised IMAP server, possibly leading to the execution of arbitrary code with the rights of the user running Balsa.
There is no known workaround at this time.
All Balsa users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=mail-client/balsa-2.3.20"