The Q.931 dissector in Ethereal before 0.10.0, and Tethereal, allows remote attackers to cause a denial of service (crash) via a malformed Q.931, which triggers a null dereference.
The SMB dissector in Ethereal before 0.10.0 allows remote attackers to cause a denial of service via a malformed SMB packet that triggers a segmentation fault during processing of Selected packets.