Full Report
Multiple Siemens products are affected by two local privilege escalation vulnerabilities which could allow an low privileged attacker to load malicious DLLs, potentially leading to arbitrary code execution with elevated privileges. Siemens has released new versions for the affected products and recommends to update to the latest versions.
Analysis Summary
# Vulnerability: Local Privilege Escalation via Malicious DLL Loading in Siemens SINEC NMS and UMC
## CVE Details
- **CVE ID:** CVE-2026-25655, CVE-2026-25656
- **CVSS Score:** 7.8 (CVSS v3.1) / 8.5 (CVSS v4.0) (High)
- **CWE:** CWE-427 (Uncontrolled Search Path Element Vulnerability)
## Affected Systems
- **Products:**
- SINEC NMS
- User Management Component (UMC)
- **Versions:**
- **CVE-2026-25655:** SINEC NMS All versions `< V4.0 SP2`
- **CVE-2026-25656:**
- SINEC NMS: All versions affected (specifics point to UMC dependency)
- UMC: All versions `< V2.15.2.1`
- **Configurations:** Local, low-privileged attacker required.
## Vulnerability Description
The advisory details two related Local Privilege Escalation (LPE) vulnerabilities stemming from improper modification of configuration files by a low-privileged user, which exploits an **Uncontrolled Search Path Element (CWE-427)** weakness. This flaw allows an attacker to influence the application's DLL search path. Successful exploitation enables the low-privileged attacker to load and execute malicious Dynamic Link Libraries (DLLs).
* **CVE-2026-25655:** Could lead to arbitrary code execution with **administrative privileges**.
* **CVE-2026-25656:** Could lead to arbitrary code execution with **SYSTEM privileges** (specifically targeting UMC).
## Exploitation
- **Status:** Not explicitly stated as exploited in the wild, but the description implies exploitability potential.
- **Complexity:** Low (AV:L, AC:L, PR:L) – Requires local access and low privileges, but attack complexity is low.
- **Attack Vector:** Local
## Impact
- **Confidentiality:** High (H)
- **Integrity:** High (H)
- **Availability:** High (H)
*(Based on CVSS v3.1 vector S:U/C:H/I:H/A:H)*
## Remediation
### Patches
The definitive solution is updating to or migrating to the patched versions:
* **For CVE-2026-25655 (SINEC NMS):** Update to **V4.0 SP2 or later version**.
* Reference Link: `https://support.industry.siemens.com/cs/ww/en/view/109998317/`
* **For CVE-2026-25656 (UMC/SINEC NMS):** Update UMC to **V2.15.2.1 or later compatible version**.
* Reference Link: `https://support.industry.siemens.com/cs/document/109996127/`
### Workarounds
No specific workarounds are detailed besides following the **General Security Recommendations**:
1. Protect network access to the devices using appropriate mechanisms.
2. Configure the environment according to Siemens' operational guidelines for Industrial Security.
## Detection
- **Indicators of Compromise:** Loading of unexpected or unauthorized DLLs from non-standard paths by the affected applications (SINEC NMS or UMC services/processes).
- **Detection methods and tools:** Traditional endpoint detection and response (EDR) tools should monitor child processes spawned by SINEC NMS or UMC that execute functions indicative of elevated privilege use, especially focusing on suspicious file load activity during application execution.
## References
- **Vendor Advisories:** SSA-311973
- **Relevant links - defanged:**
- `https://cert-portal.siemens.com/productcert/html/ssa-311973.html`
- `https://www.siemens.com/cert/operational-guidelines-industrial-security`
- `https://www.siemens.com/industrialsecurity`
- `https://www.siemens.com/cert/advisories`