{
  "containers": {
    "cna": {
      "affected": [
        {
          "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"
            }
          ]
        }
      ],
      "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."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "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"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-138",
              "description": "CWE-138: Improper Neutralization of Special Elements",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-28T22:11:08.747Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/Graylog2/graylog2-server/security/advisories/GHSA-gqr6-r77p-c2pj",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/Graylog2/graylog2-server/security/advisories/GHSA-gqr6-r77p-c2pj"
        },
        {
          "name": "https://github.com/Graylog2/graylog2-server/pull/26050",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/Graylog2/graylog2-server/pull/26050"
        },
        {
          "name": "https://github.com/Graylog2/graylog2-server/pull/26056",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/Graylog2/graylog2-server/pull/26056"
        },
        {
          "name": "https://github.com/Graylog2/graylog2-server/pull/26057",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/Graylog2/graylog2-server/pull/26057"
        },
        {
          "name": "https://github.com/Graylog2/graylog2-server/pull/26059",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/Graylog2/graylog2-server/pull/26059"
        },
        {
          "name": "https://github.com/Graylog2/graylog2-server/commit/793df6e8202ea55c15a762e47a2a8a775961dd3f",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/Graylog2/graylog2-server/commit/793df6e8202ea55c15a762e47a2a8a775961dd3f"
        },
        {
          "name": "https://github.com/Graylog2/graylog2-server/commit/85dc699d6319aea433583dc239077a3a799c8627",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/Graylog2/graylog2-server/commit/85dc699d6319aea433583dc239077a3a799c8627"
        },
        {
          "name": "https://github.com/Graylog2/graylog2-server/commit/d5051e604c962ef3d4e5e8e434d0ff4907d2140d",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/Graylog2/graylog2-server/commit/d5051e604c962ef3d4e5e8e434d0ff4907d2140d"
        },
        {
          "name": "https://github.com/Graylog2/graylog2-server/commit/dde76d7432c469887d9a95c208083c5f0f73c70d",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/Graylog2/graylog2-server/commit/dde76d7432c469887d9a95c208083c5f0f73c70d"
        }
      ],
      "source": {
        "advisory": "GHSA-gqr6-r77p-c2pj",
        "discovery": "UNKNOWN"
      },
      "title": "Graylog: Fortigate syslog message parser can be exploited to modify or delete fields from the original message"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-55841",
    "datePublished": "2026-08-28T22:11:08.747Z",
    "dateReserved": "2026-06-17T16:29:38.865Z",
    "dateUpdated": "2026-08-28T22:11:08.747Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}