CVE-2026-78359

Duplicate Identity / Identity Shadowing across CustomerUser backends

Published Oct 12, 2026 CVSS 3.1 · 5.4 Medium EPSS < 1% KEV · Not listed
Description
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

Remediation

Vendor Solution

Update to latest version of OTRS (2026.7.1. or later). Please note that there will be no OTRS 7 patches

Tracking

Sign in to view the affected projects.

Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Otrs
Otrs otrs
Otrs otrs Community Edition
Vendors & Products Otrs
Otrs otrs
Otrs otrs Community Edition
Type Values Removed Values Added
Description 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
Title Duplicate Identity / Identity Shadowing across CustomerUser backends
Weaknesses CWE-694
CWE-706
References
Metrics cvssV3_1

{'score': 5.4, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
OTRS
Published
Updated
Oct 15, 2026, 7:15 PM
Reserved
Aug 24, 2026, 11:29 AM
Status
Deferred
Published
Oct 12, 2026, 7:16 AM
Modified
Oct 15, 2026, 8:38 PM