The pcap_process_pseudo_header function in wiretap/pcap-common.c in Wireshark 1.4.x before 1.4.12 and 1.6.x before 1.6.6 allows remote attackers to cause a denial of service (application crash) via a WTAP_ENCAP_ERF file containing an Extension or Multi-Channel header with an invalid pseudoheader size, related to the pcap and pcap-ng file parsers.