Full Report
SINEC NMS before V4.0 SP3 contains an Authorization Bypass vulnerability that could allow an attacker to bypass authorization checks, leading to the ability to reset the password of any arbitrary user account. Siemens has released a new version for SINEC NMS and recommends to update to the latest version.
Analysis Summary
# Vulnerability: Authorization Bypass in Siemens SINEC NMS
## CVE Details
- **CVE ID:** CVE-2026-25654
- **CVSS Score:** 8.8 (High) - CVSS v3.1 / 8.7 (High) - CVSS v4.0
- **CWE:** CWE-639: Authorization Bypass Through User-Controlled Key
## Affected Systems
- **Products:** SINEC NMS (Network Management System)
- **Versions:** All versions prior to V4.0 SP3
- **Configurations:** Default installations processing password reset requests.
## Vulnerability Description
Affected versions of SINEC NMS fail to properly validate user authorization during the processing of password reset requests. Specifically, the application does not verify if the requesting entity has the permission to modify the target account's credentials. This allows an authenticated attacker to manipulate user-controlled keys (such as account identifiers) to bypass authorization checks and reset the password of any arbitrary user account, including administrative accounts.
## Exploitation
- **Status:** Not currently reported as exploited in the wild; PoC not public (Coordinated disclosure via Trend Micro ZDI).
- **Complexity:** Low
- **Attack Vector:** Network (Remote)
- **Authentication:** Required (Privileges: Low)
## Impact
- **Confidentiality:** High (Full account takeover possible)
- **Integrity:** High (Ability to modify administrative configurations)
- **Availability:** High (Ability to lock out legitimate users or disrupt network management)
## Remediation
### Patches
- **Update to SINEC NMS V4.0 SP3** or a later version.
- Patch Link: [https]://support.industry.siemens.com/cs/ww/en/view/110000760/
### Workarounds
- **Network Segmentation:** Limit network access to the SINEC NMS interface to trusted users and management systems only.
- **Operational Guidelines:** Adhere to Siemens' operational guidelines for Industrial Security to ensure the device operates within a protected IT environment.
## Detection
- **Indicators of Compromise:** Unusual password reset events in system audit logs, especially those originating from low-privileged accounts targeting administrative users.
- **Detection methods and tools:** Monitor network traffic for unauthorized API calls to password reset endpoints; audit SINEC NMS user activity logs for unauthorized credential changes.
## References
- **Siemens Security Advisory:** [https]://cert-portal.siemens.com/productcert/pdf/ssa-605717.pdf
- **Siemens Industrial Security Guidelines:** [https]://www.siemens.com/cert/operational-guidelines-industrial-security
- **General Advisories:** [https]://www.siemens.com/cert/advisories