GHSA-gqr6-r77p-c2pj: org.graylog2:graylog2-server (CVE-2026-55841)

Package	Ecosystem	Affected	Fixed in
org.graylog2:graylog2-server	Maven	<6.3.12 \|\| >=7.0.0, <7.0.7 \|\| >=7.1.0, <7.1.2	6.3.12, 7.0.7, 7.1.2

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

Graylog (org.graylog2:graylog2-server) versions before 6.3.12, from 7.0.0 before 7.0.7, and from 7.1.0 before 7.1.2 are affected. The parser for key-value syslog messages, such as those from Fortigate devices, can be abused to overwrite individual message fields or create invalid messages that Graylog discards, which can help hide malicious activity. Upgrade to 6.3.12, 7.0.7, 7.1.2 or later; the source lists no feasible workarounds.

Written 2 Nov 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

Score	Rating	CVSS	Vector	Source
7.5	High	3.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N	CNA (GitHub_M)

CISA KEV Not listed.
EPSS 0.0063, the 50th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

31 Oct 2026, 14:19 UTC First seen by agentprime
31 Oct 2026, 14:19 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.