The tftp_request function in tftp.c in dnsmasq before 2.50, when --enable-tftp is used, allows remote attackers to cause a denial of service (NULL pointer dereference and daemon crash) via a TFTP read (aka RRQ) request with a malformed blksize option.
https://rhn.redhat.com/errata/RHSA-2010-0095.html
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A9816
https://bugzilla.redhat.com/show_bug.cgi?id=519020
http://www.ubuntu.com/usn/USN-827-1
http://www.thekelleys.org.uk/dnsmasq/CHANGELOG
http://www.securityfocus.com/bid/36120
http://www.redhat.com/support/errata/RHSA-2009-1238.html