The init script in the Gentoo app-admin/logstash-bin package before 5.5.3 and 5.6.x before 5.6.1 has "chown -R" calls for user-writable directory trees, which allows local users to gain privileges by leveraging access to a $LS_USER account for creation of a hard link.

Logstash 1.4.x before 1.4.5 and 1.5.x before 1.5.4 with Lumberjack output or the Logstash forwarder does not validate SSL/TLS certificates from the Logstash server, which might allow attackers to obtain sensitive information via a man-in-the-middle attack.

Logstash 1.5.x before 1.5.3 and 1.4.x before 1.4.4 allows remote attackers to read communications between Logstash Forwarder agent and Logstash server.

Logstash prior to version 2.1.2, the CSV output can be attacked via engineered input that will create malicious formulas in the CSV data.

Logstash versions prior to 2.3.3, when using the Netflow Codec plugin, a remote attacker crafting malicious Netflow v5, Netflow v9 or IPFIX packets could perform a denial of service attack on the Logstash instance. The errors resulting from these crafted inputs are not handled by the codec and can cause the Logstash process to exit.

Logstash prior to version 2.3.4, Elasticsearch Output plugin would log to file HTTP authorization headers which could contain sensitive information.

Directory traversal vulnerability in the file output plugin in Elasticsearch Logstash before 1.4.3 allows remote attackers to write to arbitrary files via vectors related to dynamic field references in the path option.

Cross-site scripting (XSS) vulnerability in IPA iLogScanner 4.0 allows remote attackers to inject arbitrary web script or HTML by triggering a crafted entry in a log file.

Monitoring Agent for UNIX Logs 6.2.0 through FP03, 6.2.1 through FP04, 6.2.2 through FP09, and 6.2.3 through FP04 and Monitoring Server (ms) and Shared Libraries (ax) 6.2.0 through FP03, 6.2.1 through FP04, 6.2.2 through FP08, 6.2.3 through FP01, and 6.3.0 through FP01 in IBM Tivoli Monitoring (ITM) on UNIX allow local users to gain privileges via unspecified vectors.

Elasticsearch Logstash 1.0.14 through 1.4.x before 1.4.2 allows remote attackers to execute arbitrary commands via a crafted event in (1) zabbix.rb or (2) nagios_nsca.rb in outputs/.