CVE-2026-55841

HIGHPre-NVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4%, top 71% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.5Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
7.5
EG Score
7.5(medium)
EG Risk
49(Track)
EG Risk 49/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity75% × 45%
Exploitation0% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
29%
KEV
Not listed

Published

August 28, 2026

Last Modified

September 9, 2026

Advisory Details (9)

Auto-updated Aug 28, 2026
Patch available. Sources: github, github_pr, github_commit.
github_commit

commit dde76d7432c4 (Graylog2/graylog2-server)

Fix landed in Graylog2/graylog2-server commit dde76d7432c4 — awaiting tagged release

https://github.com/Graylog2/graylog2-server/commit/dde76d7432c469887d9a95c208083c5f0f73c70d
github_commit

commit d5051e604c96 (Graylog2/graylog2-server)

Fix landed in Graylog2/graylog2-server commit d5051e604c96 — awaiting tagged release

https://github.com/Graylog2/graylog2-server/commit/d5051e604c962ef3d4e5e8e434d0ff4907d2140d
github_commit

commit 85dc699d6319 (Graylog2/graylog2-server)

Fix landed in Graylog2/graylog2-server commit 85dc699d6319 — awaiting tagged release

https://github.com/Graylog2/graylog2-server/commit/85dc699d6319aea433583dc239077a3a799c8627
github_commit

commit 793df6e8202e (Graylog2/graylog2-server)

Fix landed in Graylog2/graylog2-server commit 793df6e8202e — awaiting tagged release

https://github.com/Graylog2/graylog2-server/commit/793df6e8202ea55c15a762e47a2a8a775961dd3f
github_pr

Fix FortiGate syslog parser handling of quoted values (`6.3`)

Fix merged in Graylog2/graylog2-server PR #26059 on 2026-05-19 — awaiting tagged release

https://github.com/Graylog2/graylog2-server/pull/26059
github_pr

Fix FortiGate syslog parser handling of quoted values (`7.0`)

Fix merged in Graylog2/graylog2-server PR #26057 on 2026-05-19 — awaiting tagged release

https://github.com/Graylog2/graylog2-server/pull/26057
github_pr

Fix FortiGate syslog parser handling of quoted values (`7.1`)

Fix merged in Graylog2/graylog2-server PR #26056 on 2026-05-19 — awaiting tagged release

https://github.com/Graylog2/graylog2-server/pull/26056
github_pr

Fix FortiGate syslog parser handling of quoted values

Fix merged in Graylog2/graylog2-server PR #26050 on 2026-05-19 — awaiting tagged release

https://github.com/Graylog2/graylog2-server/pull/26050
github Patch Available

Fortigate syslog message parser can be exploited to modify or delete fields from the original message · Advisory · Graylog2/graylog2-server · GitHub

https://github.com/Graylog2/graylog2-server/security/advisories/GHSA-gqr6-r77p-c2pj

Vendor Advisories for CVE-2026-55841(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(1 across 1 ecosystem)
Maven(1)
PackageVulnerable rangeFixed inDependents
org.graylog2:graylog2-server7.1.17.1.2—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 13× in last 7d / 42× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-09-18 23:14 UTCEG score recompute
  2. 2026-09-18 19:28 UTCEPSS rescore
  3. 2026-09-17 21:39 UTCEG score recompute
  4. 2026-09-17 19:31 UTCEPSS rescore
  5. 2026-09-16 20:03 UTCEG score recompute
  6. 2026-09-16 14:08 UTCEPSS rescore
  7. 2026-09-16 07:16 UTCEG score recompute
  8. 2026-09-16 05:15 UTCEPSS rescore
  9. 2026-09-15 05:36 UTCEG score recompute
  10. 2026-09-15 03:11 UTCEPSS rescore
  11. 2026-09-14 03:45 UTCEG score recompute
  12. 2026-09-13 16:47 UTCEPSS rescore
  13. 2026-09-13 02:11 UTCEG score recompute
  14. 2026-09-12 00:35 UTCEG score recompute
  15. 2026-09-11 14:53 UTCEPSS rescore
  16. 2026-09-11 11:48 UTCEG score recompute
  17. 2026-09-10 09:58 UTCEG score recompute
  18. 2026-09-10 09:35 UTCEPSS rescore
  19. 2026-09-09 00:25 UTCEG score recompute
  20. 2026-09-08 22:01 UTCEPSS rescore
  21. 2026-09-08 04:33 UTCEG score recompute
  22. 2026-09-07 16:01 UTCEPSS rescore
  23. 2026-09-06 14:09 UTCEG score recompute
  24. 2026-09-06 13:47 UTCEPSS rescore
  25. 2026-09-06 01:22 UTCEG score recompute
Show 17 more
  1. 2026-09-04 23:46 UTCEG score recompute
  2. 2026-09-04 10:59 UTCEG score recompute
  3. 2026-09-04 05:07 UTCEPSS rescore
  4. 2026-09-02 20:23 UTCEG score recompute
  5. 2026-09-02 14:12 UTCEPSS rescore
  6. 2026-09-01 16:19 UTCEG score recompute
  7. 2026-09-01 13:54 UTCEPSS rescore
  8. 2026-09-01 04:40 UTCEPSS rescore
  9. 2026-09-01 03:33 UTCEG score recompute
  10. 2026-09-01 02:41 UTCEG score recompute
  11. 2026-08-31 02:38 UTCEG score recompute
  12. 2026-08-30 19:17 UTCEPSS rescore
  13. 2026-08-30 13:52 UTCEG score recompute
  14. 2026-08-30 01:22 UTCEPSS rescore
  15. 2026-08-28 23:25 UTCEG score recompute
  16. 2026-08-28 22:22 UTCEG score recompute
  17. 2026-08-28 22:18 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-55841?
CVE-2026-55841 is a high vulnerability published on August 28, 2026. 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…
When was CVE-2026-55841 disclosed?
CVE-2026-55841 was first published in the National Vulnerability Database on August 28, 2026, with the most recent update on September 9, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-55841 actively exploited?
CVE-2026-55841 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 70.7% of all scored CVEs.
What is the CVSS score of CVE-2026-55841?
CVE-2026-55841 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-55841?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-55841, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-55841

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