Description
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 graylog2-server/src/main/java/org/graylog2/inputs/codecs/SyslogCodec.java mishandles field-like text inside quoted values. GLFortiGateSyslogEvent.getFields() uses KV_PATTERN and QUOTED_KV_PATTERN, while SyslogCodec.parse() invokes the FortiGateSyslogEvent parser; crafted values containing = or backslash-escaped quotes can cause embedded keys such as srcip, dstip, date, time, and tz to remove or overwrite original top-level fields or produce an invalid message that Graylog discards. An unauthenticated network sender who can submit syslog messages can therefore manipulate security-log fields or evade logging to obscure malicious activity. This issue is fixed in Graylog Server versions 6.3.12, 7.0.7, and 7.1.2 and Graylog Forwarder version 7.3.
References9
- github.com/Graylog2/graylog2-server/commit/793df6e8202ea55c15a7…
- github.com/Graylog2/graylog2-server/commit/85dc699d6319aea43358…
- github.com/Graylog2/graylog2-server/commit/d5051e604c962ef3d4e5…
- github.com/Graylog2/graylog2-server/commit/dde76d7432c469887d9a…
- github.com/Graylog2/graylog2-server/pull/26050
- github.com/Graylog2/graylog2-server/pull/26056
- github.com/Graylog2/graylog2-server/pull/26057
- github.com/Graylog2/graylog2-server/pull/26059
- github.com/Graylog2/graylog2-server/security/advisories/GHSA-gq…
Metrics
- CVSS 3.1
-
7.5
HIGH
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N - EPSS — exploit probability
- 1% percentile: 51 · as of 8 November 2026
- CWE
- CWE-138
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