Dnsmasq is a lightweight and easily-configurable DNS forwarder and DHCP server.
A remote attacker could send spoofed DNS response traffic to dnsmasq, possibly involving generating queries via multiple vectors, and spoof DNS replies, which could e.g. lead to the redirection of web or mail traffic to malicious sites. Furthermore, an attacker could generate invalid DHCP traffic and cause a Denial of Service.
There is no known workaround at this time.
All dnsmasq users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=net-dns/dnsmasq-2.45"