In Suricata before 4.x, it was possible to trigger lots of redundant checks on the content of crafted network traffic with a certain signature, because of DetectEngineContentInspection in detect-engine-content-inspection.c. The search engine doesn't stop when it should after no match is found; instead, it stops only upon reaching inspection-recursion-limit (3000 by default).

Suricata before 3.2.1 has an IPv4 defragmentation evasion issue caused by lack of a check for the IP protocol during fragment matching.

The DER parser in Suricata before 2.0.8 allows remote attackers to cause a denial of service (crash) via vectors related to SSL/TLS certificates.

The MemcmpLowercase function in Suricata before 2.0.6 improperly excludes the first byte from comparisons, which might allow remote attackers to bypass intrusion-prevention functionality via a crafted HTTP request.

The SSHParseBanner function in SSH parser (app-layer-ssh.c) in Suricata before 2.0.4 allows remote attackers to bypass SSH rules, cause a denial of service (crash), or possibly have unspecified other impact via a crafted banner, which triggers a large memory allocation or an out-of-bounds write.

Suricata before 1.4.6 allows remote attackers to cause a denial of service (crash) via a malformed SSL record.