Dropbear is an SSH server and client designed with a small memory footprint.
Multiple vulnerabilities have been discovered in Dropbear. Please review the CVE identifier and Gentoo bug referenced below for details.
A remote attacker could send a specially crafted request to trigger a use-after-free condition, possibly resulting in arbitrary code execution or a Denial of Service condition. Additionally, the bundled version of libtommath has an error in its prime number generation, which could result in the generation of weak keys.
There is no known workaround at this time.
All Dropbear users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=net-misc/dropbear-2012.55"