The (1) dissect_tfs_request and (2) dissect_tfs_response functions in epan/dissectors/packet-ieee80211.c in the IEEE 802.11 dissector in Wireshark 1.10.x before 1.10.14 and 1.12.x before 1.12.5 interpret a zero value as a length rather than an error condition, which allows remote attackers to cause a denial of service (infinite loop) via a crafted packet.