FKIE_CVE-2026-55841

Vulnerability from fkie_nvd - Published: 2026-08-28 23:17 - Updated: 2026-08-28 23:17
Severity
7.5 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Summary
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.
References
security-advisories@github.comhttps://github.com/Graylog2/graylog2-server/commit/793df6e8202ea55c15a762e47a2a8a775961dd3f
security-advisories@github.comhttps://github.com/Graylog2/graylog2-server/commit/85dc699d6319aea433583dc239077a3a799c8627
security-advisories@github.comhttps://github.com/Graylog2/graylog2-server/commit/d5051e604c962ef3d4e5e8e434d0ff4907d2140d
security-advisories@github.comhttps://github.com/Graylog2/graylog2-server/commit/dde76d7432c469887d9a95c208083c5f0f73c70d
security-advisories@github.comhttps://github.com/Graylog2/graylog2-server/pull/26050
security-advisories@github.comhttps://github.com/Graylog2/graylog2-server/pull/26056
security-advisories@github.comhttps://github.com/Graylog2/graylog2-server/pull/26057
security-advisories@github.comhttps://github.com/Graylog2/graylog2-server/pull/26059
security-advisories@github.comhttps://github.com/Graylog2/graylog2-server/security/advisories/GHSA-gqr6-r77p-c2pj
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "graylog2-server",
          "vendor": "Graylog2",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 6.3.12"
            },
            {
              "status": "affected",
              "version": "\u003e= 7.0.0-alpha.1, \u003c 7.0.7"
            },
            {
              "status": "affected",
              "version": "\u003e= 7.1.0-alpha.1, \u003c 7.1.2"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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."
    }
  ],
  "id": "CVE-2026-55841",
  "lastModified": "2026-08-28T23:17:07.840",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 7.5,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "NONE",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 3.6,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-08-28T23:17:07.840",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/Graylog2/graylog2-server/commit/793df6e8202ea55c15a762e47a2a8a775961dd3f"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/Graylog2/graylog2-server/commit/85dc699d6319aea433583dc239077a3a799c8627"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/Graylog2/graylog2-server/commit/d5051e604c962ef3d4e5e8e434d0ff4907d2140d"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/Graylog2/graylog2-server/commit/dde76d7432c469887d9a95c208083c5f0f73c70d"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/Graylog2/graylog2-server/pull/26050"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/Graylog2/graylog2-server/pull/26056"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/Graylog2/graylog2-server/pull/26057"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/Graylog2/graylog2-server/pull/26059"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/Graylog2/graylog2-server/security/advisories/GHSA-gqr6-r77p-c2pj"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Received",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-138"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Primary"
    }
  ]
}



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Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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