{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-55841",
        "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "state": "PUBLISHED",
        "assignerShortName": "GitHub_M",
        "dateReserved": "2026-06-17T16:29:38.865Z",
        "datePublished": "2026-08-28T22:11:08.747Z",
        "dateUpdated": "2026-08-28T22:11:08.747Z"
    },
    "containers": {
        "cna": {
            "title": "Graylog: Fortigate syslog message parser can be exploited to modify or delete fields from the original message",
            "problemTypes": [
                {
                    "descriptions": [
                        {
                            "cweId": "CWE-138",
                            "lang": "en",
                            "description": "CWE-138: Improper Neutralization of Special Elements",
                            "type": "CWE"
                        }
                    ]
                }
            ],
            "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"
                    }
                }
            ],
            "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"
                }
            ],
            "affected": [
                {
                    "vendor": "Graylog2",
                    "product": "graylog2-server",
                    "versions": [
                        {
                            "version": "< 6.3.12",
                            "status": "affected"
                        },
                        {
                            "version": ">= 7.0.0-alpha.1, < 7.0.7",
                            "status": "affected"
                        },
                        {
                            "version": ">= 7.1.0-alpha.1, < 7.1.2",
                            "status": "affected"
                        }
                    ]
                }
            ],
            "providerMetadata": {
                "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
                "shortName": "GitHub_M",
                "dateUpdated": "2026-08-28T22:11:08.747Z"
            },
            "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."
                }
            ],
            "source": {
                "advisory": "GHSA-gqr6-r77p-c2pj",
                "discovery": "UNKNOWN"
            }
        }
    }
}