What’s Vulnerable › Vulnerabilities
CVE-2026-78359: Duplicate Identity / Identity Shadowing across CustomerUser backends
- Severity: medium (CVSS 5.4 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.2% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-10-12 · updated 2026-10-15
- Weakness: CWE-694
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
Affected products
- OTRS GmbH (former OTRS AG) OTRS: from 2026.x through 2026.6.x; 7.0.x, 8.0.x, 2023.x, 2024.x, 2025.x
- OTRS GmbH (former OTRS AG) ((OTRS)) Community Edition: 6.x
References
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