Multiple vulnerabilities in the IGMP functionality for Linux kernel 2.4.22 to 2.4.28, and 2.6.x to 2.6.9, allow local and remote attackers to cause a denial of service or execute arbitrary code via (1) the ip_mc_source function, which decrements a counter to -1, or (2) the igmp_marksources function, which does not properly validate IGMP message parameters and performs an out-of-bounds read.