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.

The HTTP Inspect preprocessor (http_inspect) in Snort 2.4.0 through 2.4.4 allows remote attackers to bypass "uricontent" rules via a carriage return (\r) after the URL and before the HTTP declaration.

The frag3 preprocessor in Sourcefire Snort 2.4.3 does not properly reassemble certain fragmented packets with IP options, which allows remote attackers to evade detection of certain attacks, possibly related to IP option lengths.

Stack-based buffer overflow in the Back Orifice (BO) preprocessor for Snort before 2.4.3 allows remote attackers to execute arbitrary code via a crafted UDP packet.

The DecodeTCPOptions function in decode.c in Snort before 2.3.0, when printing TCP/IP options using FAST output or verbose mode, allows remote attackers to cause a denial of service (crash) via packets with invalid TCP/IP options, which trigger a null dereference.

Integer overflow in the TCP stream reassembly module (stream4) for Snort 2.0 and earlier allows remote attackers to execute arbitrary code via large sequence numbers in packets, which enable a heap-based buffer overflow.