Snort before 2.8.5.1, when the -v option is enabled, allows remote attackers to cause a denial of service (application crash) via a crafted IPv6 packet that uses the (1) TCP or (2) ICMP protocol.

preprocessors/spp_frag3.c in Sourcefire Snort before 2.8.1 does not properly identify packet fragments that have dissimilar TTL values, which allows remote attackers to bypass detection rules by using a different TTL for each fragment.

The frag3 preprocessor in Snort 2.6.1.1, 2.6.1.2, and 2.7.0 beta, when configured for inline use on Linux without the ip_conntrack module loaded, allows remote attackers to cause a denial of service (segmentation fault and application crash) via certain UDP packets produced by send_morefrag_packet and send_overlap_packet.

Stack-based buffer overflow in the DCE/RPC preprocessor in Snort before 2.6.1.3, and 2.7 before beta 2; and Sourcefire Intrusion Sensor; allows remote attackers to execute arbitrary code via crafted SMB traffic.

Algorithmic complexity vulnerability in Snort before 2.6.1, during predicate evaluation in rule matching for certain rules, allows remote attackers to cause a denial of service (CPU consumption and detection outage) via crafted network traffic, aka a "backtracking attack."

Integer underflow in the DecodeGRE function in src/decode.c in Snort 2.6.1.2 allows remote attackers to trigger dereferencing of certain memory locations via crafted GRE packets, which may cause corruption of log files or writing of sensitive information into log files.

Buffer overflow in the RPC preprocessor for Snort 1.8 and 1.9.x before 1.9.1 allows remote attackers to execute arbitrary code via fragmented RPC packets.

SnortCenter 0.9.5, when configured to push Snort rules, stores the rules in a temporary file with world-readable and world-writable permissions, which allows local users to obtain usernames and passwords for the alert database servers.

Unknown vulnerability in IP defragmenter (frag2) in Snort before 1.8.3 allows attackers to cause a denial of service (crash).

Various Intrusion Detection Systems (IDS) including (1) Cisco Secure Intrusion Detection System, (2) Cisco Catalyst 6000 Intrusion Detection System Module, (3) Dragon Sensor 4.x, (4) Snort before 1.8.1, (5) ISS RealSecure Network Sensor 5.x and 6.x before XPU 3.2, and (6) ISS RealSecure Server Sensor 5.5 and 6.0 for Windows, allow remote attackers to evade detection of HTTP attacks via non-standard "%u" Unicode encoding of ASCII characters in the requested URL.