CVE-2026-78359 (GCVE-0-2026-78359)

Vulnerability from cvelistv5 – Published: 2026-10-12 06:49 – Updated: 2026-10-12 06:49
VLAI
Title
Duplicate Identity / Identity Shadowing across CustomerUser backends
Summary
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. 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. The vulnerability does not allow unauthenticated users to create customer accounts. Exploitation requires permissions to create or modify customer users. This issue affects OTRS: * 7.0.X * 8.0.X * 2023.X * 2024.X * 2025.X * 2026.X before 2026.7.X 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
Severity
5.4 (Medium)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
CWE
  • CWE-694 - Use of Multiple Resources with Duplicate Identifier
  • CWE-706 - Use of Incorrectly-Resolved Name or Reference
Assigner
OTRS CNA under the mitre root
CNA scorecard B 75/100 over 18 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
OTRS GmbH (former OTRS AG) OTRS Affected: 7.0.x
Affected: 8.0.x
Affected: 2023.x
Affected: 2024.x
Affected: 2025.x
Affected: 2026.x , ≤ 2026.6.x (patch)
guessed Create a notification for this product.
OTRS GmbH (former OTRS AG) ((OTRS)) Community Edition Affected: 6.x
guessed Create a notification for this product.
Date Public
2026-10-12 07:00
Credits
Special thanks to Marc Hörsken for reporting this vulnerability
Show details on NVD website
To clipboard 

{
  "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 H\u00f6rsken for reporting this vulnerability"
        }
      ],
      "datePublic": "2026-10-12T07:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "\u003cp\u003eOTRS does not sufficiently enforce the uniqueness of customer user identities across multiple configured CustomerUser backends.\u0026nbsp;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.\u003c/p\u003e\u003cp\u003eThis 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.\u003c/p\u003e\u003cp\u003eThe vulnerability does not allow unauthenticated users to create customer accounts. Exploitation requires permissions to create or modify customer users.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThis issue affects OTRS:\u003c/p\u003e\u003cul\u003e\u003cli\u003e7.0.X\u003c/li\u003e\u003cli\u003e8.0.X\u003c/li\u003e\u003cli\u003e2023.X\u003c/li\u003e\u003cli\u003e2024.X\u003c/li\u003e\u003cli\u003e2025.X\u003c/li\u003e\u003cli\u003e2026.X before 2026.7.X\u003c/li\u003e\u003c/ul\u003ePlease note that ((OTRS)) Community Edition 6.x and before are vulnerable. Products based on the ((OTRS)) Community Edition also very likely to be affected\u003cbr\u003e\u003cp\u003e\u003c/p\u003e\u003cbr\u003e"
            }
          ],
          "value": "OTRS does not sufficiently enforce the uniqueness of customer user identities across multiple configured CustomerUser backends.\u00a0When 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": {
        "dateUpdated": "2026-10-12T06:49:24.983Z",
        "orgId": "2e1bf29f-dc29-4ed8-830c-7b9348b6f0e8",
        "shortName": "OTRS"
      },
      "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\u003cbr\u003e"
            }
          ],
          "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"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "2e1bf29f-dc29-4ed8-830c-7b9348b6f0e8",
    "assignerShortName": "OTRS",
    "cveId": "CVE-2026-78359",
    "datePublished": "2026-10-12T06:49:24.983Z",
    "dateReserved": "2026-08-24T11:29:41.427Z",
    "dateUpdated": "2026-10-12T06:49:24.983Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-78359",
      "date": "2026-10-13",
      "epss": "0.00163",
      "percentile": "0.05134"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "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"
                  }
                ]
              }
            ],
            "source": "security@otrs.com"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "OTRS does not sufficiently enforce the uniqueness of customer user identities across multiple configured CustomerUser backends.\u00a0When 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"
          }
        ],
        "id": "CVE-2026-78359",
        "lastModified": "2026-10-12T07:16:37.423",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "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"
              },
              "exploitabilityScore": 2.8,
              "impactScore": 2.5,
              "source": "security@otrs.com",
              "type": "Secondary"
            }
          ]
        },
        "published": "2026-10-12T07:16:37.423",
        "references": [
          {
            "source": "security@otrs.com",
            "url": "https://otrs.com/release-notes/otrs-security-advisory-2026-16/"
          }
        ],
        "sourceIdentifier": "security@otrs.com",
        "vulnStatus": "Received",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-694"
              },
              {
                "lang": "en",
                "value": "CWE-706"
              }
            ],
            "source": "security@otrs.com",
            "type": "Secondary"
          }
        ]
      }
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.