---
cve: "CVE-2026-55841"
severity: "HIGH"
cvss: 7.5
epss: "0.4%"
vendor: "Graylog2"
kev: false
exploited: false
published: "2026-08-28 23:17:07"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-27T11:31:36+02:00"
---

# CVE-2026-55841

> 7.5 HIGH · 🧪 PoC

## Beschreibung

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.

## CISA-Anreicherung (vulnrichment/ADP)

- CISA-SSVC (Coordinator, v2.0.3):
  - Exploitation: **none**
  - Automatable: **yes**
  - Technical Impact: **partial**

## CVSS-Vektor

```
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |
| S Scope | Unverändert | good |
| C Vertraulichkeit | Keine | good |
| I Integrität | Hoch | bad |
| A Verfügbarkeit | Keine | good |

## Patch verfügbar (OSV)

- fd62097b3ac4d3f18641e973e4823ed9bf663122 (Commit)
- 5cd524ef532ecf6c77fe5efebcd0d2a5143f893c (Commit)

## BSI-Hinweise (deutsch)

- [Graylog: Mehrere Schwachstellen](https://wid.cert-bund.de/portal/wid/sicherheitshinweis/WID-SEC-W-2026-3088)

## Referenzen

- <https://github.com/Graylog2/graylog2-server/security/advisories/GHSA-gqr6-r77p-c2pj>
- <https://github.com/Graylog2/graylog2-server/pull/26050>
- <https://github.com/Graylog2/graylog2-server/pull/26056>
- <https://github.com/Graylog2/graylog2-server/pull/26057>
- <https://github.com/Graylog2/graylog2-server/pull/26059>
- <https://github.com/Graylog2/graylog2-server/commit/793df6e8202ea55c15a762e47a2a8a775961dd3f>
- <https://github.com/Graylog2/graylog2-server/commit/85dc699d6319aea433583dc239077a3a799c8627>
- <https://github.com/Graylog2/graylog2-server/commit/d5051e604c962ef3d4e5e8e434d0ff4907d2140d>
- <https://github.com/Graylog2/graylog2-server/commit/dde76d7432c469887d9a95c208083c5f0f73c70d>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-55841) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI WID (CSAF)_