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NVD / CVE Program· CNA GitHub_M

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

Noroxi assessment

Priority: Monitor (action score 30/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.63% (FIRST EPSS); higher than 50% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: org.graylog2:graylog2-server (Maven) 7.0.7, 7.1.2, 6.3.12.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to org.graylog2:graylog2-server (Maven) 7.0.7, 7.1.2, 6.3.12 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

HighCVSS 7.5 · v3.1—No exploit Fix available
Published
Aug 28, 2026
Updated
Sep 9, 2026
EPSS
0.6% · 50th percentile

Report tools

JSON

Action score

30

Monitor

Low priority for now.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.6%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · GitHub_M
7.5
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • Graylog2 graylog2-server

    • < 6.3.12, >= 7.0.0-alpha.1, < 7.0.7, >= 7.1.0-alpha.1, < 7.1.2affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Mavenorg.graylog2:graylog2-serverfrom 7.0.0 · before 7.0.77.0.7
Mavenorg.graylog2:graylog2-serverfrom 7.1.0 · before 7.1.27.1.2
Mavenorg.graylog2:graylog2-serverbefore 6.3.126.3.12

Same product

graylog2: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-92789Graylog through 7.1.4 Server-Side Request Forgery via HTTP Redirect
    28Monitor
  • CVE-2026-69190Graylog: Manager-to-Owner privilege escalation on saved searches and dashboards
    25Monitor
  • CVE-2026-55867Graylog token revocation endpoint allows authenticated users to delete other users’ access tokens
    21Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2026-65011Jul 22, 2026 · Graylog2 Server Missing Permission Check on Event Definition Duplicate
    21Monitor
  • ← EarlierCVE-2026-55425Aug 28, 2026 · Graylog: System Catalog titles endpoint can be used to retrieve values of protected database fields
    20Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Maven:org.graylog2:graylog2-server6.3.12Package registry (OSV)
Maven:org.graylog2:graylog2-server7.0.7Package registry (OSV)
Maven:org.graylog2:graylog2-server7.1.2Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
high · data or configuration can be modified
Availability
none
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
High
Availability impact
None

Weakness class (CWE)

CWE-138 · Improper Neutralization of Special Elements

CVSS vector

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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (8 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records