CVE-2026-48190: OTRS Auth Bypass Vulnerability

CVE-2026-48190 Overview

CVE-2026-48190 is an incorrect permission handling vulnerability in the OTRS External Interface and the ConfigItem List module. The flaw allows an authenticated customer to query the system for Configuration Item (CI) information that should be restricted. The issue only affects deployments where the Configuration Management Database (CMDB) is enabled and CustomerGroupSupport is in use. Affected versions span 7.0.X, 8.0.X, 2023.X, 2024.X, 2025.X, and 2026.X releases prior to 2026.4.X. The vulnerability is categorized under [CWE-276] Incorrect Default Permissions.

Critical Impact

Authenticated customer users can retrieve Configuration Item data outside their authorized scope, leading to disclosure of CMDB inventory information.

Affected Products

• OTRS 7.0.X and 8.0.X
• OTRS 2023.X, 2024.X, and 2025.X
• OTRS 2026.X before 2026.4.X

Discovery Timeline

• 2026-06-01 - CVE-2026-48190 published to NVD
• 2026-06-01 - Last updated in NVD database

Technical Details for CVE-2026-48190

Vulnerability Analysis

The vulnerability stems from improper permission enforcement within the OTRS External Interface and the ConfigItem List module. When the CMDB feature is enabled and CustomerGroupSupport governs access, the affected components fail to fully apply group-based access controls. As a result, an authenticated customer can issue queries against the ConfigItem List endpoint and receive CI records that should remain restricted by group membership.

The vulnerability requires network access, low privileges (an authenticated customer account), and user interaction to trigger. Successful exploitation impacts confidentiality only; integrity and availability remain unaffected. No data modification or service disruption is possible through this flaw.

Root Cause

The root cause is incorrect handling of permissions [CWE-276] in the External Interface code path that serves ConfigItem queries. The module does not consistently validate the customer user's group permissions against the requested CI records before returning data. The combination of an enabled CMDB and CustomerGroupSupport is required for the affected code path to be reachable.

Attack Vector

An attacker holding any valid customer account on a vulnerable OTRS instance can interact with the External Interface and request ConfigItem listings. The server returns CI information that the customer's group membership would otherwise prohibit. The disclosure is limited to CMDB content exposed through the ConfigItem List module.

No verified proof-of-concept code is published for this issue. Refer to the OTRS Security Advisory 2026-04 for vendor technical details.

Detection Methods for CVE-2026-48190

Indicators of Compromise

• Customer External Interface sessions issuing repeated ConfigItem List queries beyond their expected workflow.
• Application logs showing successful CI record retrieval by customer accounts not assigned to the relevant CMDB groups.
• Unusual volume of CMDB read activity originating from a single customer session.

Detection Strategies

• Review OTRS application and web server logs for External Interface requests targeting ConfigItem endpoints.
• Correlate customer user identifiers against CustomerGroupSupport group assignments to identify out-of-scope CI access.
• Audit historical CMDB query patterns to baseline expected customer access and flag deviations.

Monitoring Recommendations

• Enable verbose access logging on the OTRS External Interface and forward logs to a central analytics platform.
• Alert on ConfigItem List requests from customer accounts where group membership does not authorize the returned CIs.
• Track authentication events for customer users and correlate with subsequent CMDB query activity.

How to Mitigate CVE-2026-48190

Immediate Actions Required

• Upgrade affected OTRS instances to version 2026.4.X or later as released by the vendor.
• If immediate patching is not possible, review whether CMDB and CustomerGroupSupport must remain enabled in the External Interface.
• Audit existing customer accounts and revoke unused or stale credentials that could be leveraged to query CIs.

Patch Information

OTRS has addressed the vulnerability in the 2026.4.X release line. Customers running 7.0.X, 8.0.X, 2023.X, 2024.X, 2025.X, or earlier 2026.X versions should upgrade to a fixed release. Consult the OTRS Security Advisory 2026-04 for upgrade guidance and supported migration paths.

Workarounds

• Disable the CMDB feature on the External Interface where CI data is not required by customer users.
• Restrict External Interface exposure to trusted networks or place it behind an authenticating reverse proxy.
• Tighten CustomerGroupSupport group memberships so that customer accounts hold only the minimum permissions necessary.

# Configuration example: limit External Interface exposure at the reverse proxy
# Allow only internal CIDR ranges to reach the OTRS External Interface
location /otrs/customer.pl {
    allow 10.0.0.0/8;
    deny  all;
    proxy_pass http://otrs-backend;
}