Improper Input Validation

Graylog is vulnerable to Improper Input Validation. The vulnerability is due to improper parsing of field-like text and escaped quotes within quoted FortiGate syslog values, which allows an unauthenticated network attacker to manipulate or overwrite security-log fields or cause messages to be...

CVE-2026-55841

Graylog is a free and open log management platform. Prior to Graylog Server versions 6.3.12, 7.0.7, and 7.1.2 and Graylog Forwarder version 7.3, the FortiGate key-value syslog parser in graylog2-server/src/main/java/org/graylog2/inputs/codecs/GLFortiGateSyslogEvent.java and...

Fortigate syslog message parser can be exploited to modify or delete fields from the original message

Impact A security issue has been identified in Graylog affecting the parsing of syslog messages that use a key-value format, such as those generated by Fortigate devices. The vulnerability allows attackers to overwrite individual message fields, or to produce invalid messages which Graylog will...

CVE-2026-55841

Graylog (a free and open log management platform) is affected by a parsing flaw in its FortiGate key-value syslog parser (GLFortiGateSyslogEvent.java and SyslogCodec.java). The root cause is that KV_PATTERN and QUOTED_KV_PATTERN mishandle field-like text inside quoted values: crafted values conta...

CVE-2026-55841 Graylog: Fortigate syslog message parser can be exploited to modify or delete fields from the original message

Graylog is a free and open log management platform. Prior to Graylog Server versions 6.3.12, 7.0.7, and 7.1.2 and Graylog Forwarder version 7.3, the FortiGate key-value syslog parser in graylog2-server/src/main/java/org/graylog2/inputs/codecs/GLFortiGateSyslogEvent.java and...

CVE-2026-55841

Graylog is a free and open log management platform. Prior to Graylog Server versions 6.3.12, 7.0.7, and 7.1.2 and Graylog Forwarder version 7.3, the FortiGate key-value syslog parser in graylog2-server/src/main/java/org/graylog2/inputs/codecs/GLFortiGateSyslogEvent.java and...

CVE-2026-55841 Graylog: Fortigate syslog message parser can be exploited to modify or delete fields from the original message

Graylog is a free and open log management platform. Prior to Graylog Server versions 6.3.12, 7.0.7, and 7.1.2 and Graylog Forwarder version 7.3, the FortiGate key-value syslog parser in graylog2-server/src/main/java/org/graylog2/inputs/codecs/GLFortiGateSyslogEvent.java and...