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Local Privilege Escalation to SYSTEM via DLL Search Path Hijack in Siemens SINEC NMS / UMC

IdentifiersCVE-2026-25656CWE-427· Uncontrolled Search Path Element

CVE-2026-25656 is a local privilege escalation vulnerability in Siemens SINEC NMS (all versions) and the SINEC NMS User Management Component (UMC) in versions prior to V2.15.2.1. A low-privileged local user can improperly modify a configuration file in a way that influences DLL loading (uncontrolled search path element). The product subsequently loads attacker-controlled DLLs (described in reporting as involving OpenSSL configuration being loaded from an unsecured location), which can result in execution of arbitrary code in the context of the affected elevated process/service, up to SYSTEM. (ZDI-CAN-28108; Siemens advisory SSA-311973).

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation allows a local attacker with low privileges to escalate to SYSTEM and execute arbitrary code with full control over the host, with consequent high impact to confidentiality, integrity, and availability (CVSS v3.1 7.8; AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).

Mitigation

If you can’t patch tonight, do this now.

If immediate patching is not possible, reduce exploitability by ensuring configuration files/directories that influence DLL search paths are not writable by non-admin users; enforce least privilege for local accounts; harden/limit local and remote access paths to the host; and monitor for suspicious configuration file modifications and anomalous DLL loads (e.g., DLLs loaded from user-writable paths). Application control/allowlisting can further reduce risk of unauthorized DLL loading.

Remediation

Patch, then assume compromise.

Apply Siemens’ fix by upgrading to a patched release: update SINEC NMS UMC to V2.15.2.1 or later (and follow Siemens ProductCERT guidance in SSA-311973 for compatible fixed versions/updates for SINEC NMS/UMC deployments).
PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType
SiemensSinec Nmsapplication
SiemensUser Management Componentapplication

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What this page doesn’t show

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Exposure mapping

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Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity4

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