{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-78359",
        "assignerOrgId": "2e1bf29f-dc29-4ed8-830c-7b9348b6f0e8",
        "state": "PUBLISHED",
        "assignerShortName": "OTRS",
        "dateReserved": "2026-08-24T11:29:41.427Z",
        "datePublished": "2026-10-12T06:49:24.983Z",
        "dateUpdated": "2026-10-12T06:49:24.983Z"
    },
    "containers": {
        "cna": {
            "affected": [
                {
                    "defaultStatus": "unaffected",
                    "product": "OTRS",
                    "vendor": "OTRS GmbH (former OTRS AG)",
                    "versions": [
                        {
                            "status": "affected",
                            "version": "7.0.x"
                        },
                        {
                            "status": "affected",
                            "version": "8.0.x"
                        },
                        {
                            "status": "affected",
                            "version": "2023.x"
                        },
                        {
                            "status": "affected",
                            "version": "2024.x"
                        },
                        {
                            "status": "affected",
                            "version": "2025.x"
                        },
                        {
                            "lessThanOrEqual": "2026.6.x",
                            "status": "affected",
                            "version": "2026.x",
                            "versionType": "patch"
                        }
                    ]
                },
                {
                    "defaultStatus": "affected",
                    "product": "((OTRS)) Community Edition",
                    "vendor": "OTRS GmbH (former OTRS AG)",
                    "versions": [
                        {
                            "status": "affected",
                            "version": "6.x"
                        }
                    ]
                }
            ],
            "credits": [
                {
                    "lang": "en",
                    "type": "reporter",
                    "value": "Special thanks to Marc Hörsken for reporting this vulnerability"
                }
            ],
            "datePublic": "2026-10-12T07:00:00.000Z",
            "descriptions": [
                {
                    "lang": "en",
                    "supportingMedia": [
                        {
                            "base64": false,
                            "type": "text/html",
                            "value": "<p>OTRS does not sufficiently enforce the uniqueness of customer user identities across multiple configured CustomerUser backends.&nbsp;When multiple backends, such as a database and LDAP, are configured, the uniqueness check for customer user email addresses is performed only within the selected backend. As a result, an authenticated user with permission to create or modify customer users may create a customer user whose email address is already assigned to a customer user in another backend.</p><p>This can result in multiple customer user records representing the same communication identity. Depending on the affected workflow and backend resolution, customer-related information or email communication may subsequently be associated with or exposed to the wrong customer user.</p><p>The vulnerability does not allow unauthenticated users to create customer accounts. Exploitation requires permissions to create or modify customer users.</p><p></p><p>This issue affects OTRS:</p><ul><li>7.0.X</li><li>8.0.X</li><li>2023.X</li><li>2024.X</li><li>2025.X</li><li>2026.X before 2026.7.X</li></ul>Please note that ((OTRS)) Community Edition 6.x and before are vulnerable. Products based on the ((OTRS)) Community Edition also very likely to be affected<br><p></p><br>"
                        }
                    ],
                    "value": "OTRS does not sufficiently enforce the uniqueness of customer user identities across multiple configured CustomerUser backends. When multiple backends, such as a database and LDAP, are configured, the uniqueness check for customer user email addresses is performed only within the selected backend. As a result, an authenticated user with permission to create or modify customer users may create a customer user whose email address is already assigned to a customer user in another backend.\n\nThis can result in multiple customer user records representing the same communication identity. Depending on the affected workflow and backend resolution, customer-related information or email communication may subsequently be associated with or exposed to the wrong customer user.\n\nThe vulnerability does not allow unauthenticated users to create customer accounts. Exploitation requires permissions to create or modify customer users.\n\nThis issue affects OTRS:\n\n  *  7.0.X\n  *  8.0.X\n  *  2023.X\n  *  2024.X\n  *  2025.X\n  *  2026.X before 2026.7.X\n\nPlease note that ((OTRS)) Community Edition 6.x and before are vulnerable. Products based on the ((OTRS)) Community Edition also very likely to be affected"
                }
            ],
            "impacts": [
                {
                    "capecId": "CAPEC-151",
                    "descriptions": [
                        {
                            "lang": "en",
                            "value": "CAPEC-151 Identity Spoofing"
                        }
                    ]
                }
            ],
            "metrics": [
                {
                    "cvssV3_1": {
                        "attackComplexity": "LOW",
                        "attackVector": "NETWORK",
                        "availabilityImpact": "NONE",
                        "baseScore": 5.4,
                        "baseSeverity": "MEDIUM",
                        "confidentialityImpact": "LOW",
                        "integrityImpact": "LOW",
                        "privilegesRequired": "LOW",
                        "scope": "UNCHANGED",
                        "userInteraction": "NONE",
                        "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N",
                        "version": "3.1"
                    },
                    "format": "CVSS",
                    "scenarios": [
                        {
                            "lang": "en",
                            "value": "GENERAL"
                        }
                    ]
                }
            ],
            "problemTypes": [
                {
                    "descriptions": [
                        {
                            "cweId": "CWE-694",
                            "description": "CWE-694 Use of Multiple Resources with Duplicate Identifier",
                            "lang": "en",
                            "type": "CWE"
                        }
                    ]
                },
                {
                    "descriptions": [
                        {
                            "cweId": "CWE-706",
                            "description": "CWE-706 Use of Incorrectly-Resolved Name or Reference",
                            "lang": "en",
                            "type": "CWE"
                        }
                    ]
                }
            ],
            "providerMetadata": {
                "orgId": "2e1bf29f-dc29-4ed8-830c-7b9348b6f0e8",
                "shortName": "OTRS",
                "dateUpdated": "2026-10-12T06:49:24.983Z"
            },
            "references": [
                {
                    "url": "https://otrs.com/release-notes/otrs-security-advisory-2026-16/"
                }
            ],
            "solutions": [
                {
                    "lang": "en",
                    "supportingMedia": [
                        {
                            "base64": false,
                            "type": "text/html",
                            "value": "Update to latest version of OTRS (2026.7.1. or later). Please note that there will be no OTRS 7 patches<br>"
                        }
                    ],
                    "value": "Update to latest version of OTRS (2026.7.1. or later). Please note that there will be no OTRS 7 patches"
                }
            ],
            "source": {
                "advisory": "OSA-2026-16",
                "defect": [
                    "SecOPS#2026060110000125",
                    "Issue#5088"
                ],
                "discovery": "EXTERNAL"
            },
            "title": "Duplicate Identity / Identity Shadowing across CustomerUser backends",
            "x_generator": {
                "engine": "Vulnogram 0.1.0-dev"
            }
        }
    }
}