CVE-2026-85115: Medium severity Siemens .NET Client Library for SIMATIC S7 Webserver API vulnerability
A vulnerability has been identified in .NET Client Library for SIMATIC S7 Webserver API (All versions < V3.3.62). Affected applications do not properly redact PLC restore passwords from HTTP error exception messages. This could allow an attacker with access to logs or other diagnostic output to obtain the plaintext restore password and potentially perform unauthorized operations on the PLC.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
.NET Client Library for SIMATIC S7 Webserver APIto a version that resolves this vulnerability.Fixed in V3.3.62
Event History
Frequently Asked Questions
Who is exposed to this issue?
Applications using the Siemens .NET Client Library for SIMATIC S7 Webserver API in versions earlier than V3.3.62 are affected if their HTTP error exception messages are written to logs or other diagnostic output accessible to an attacker.
What access does an attacker need to obtain the password?
The attacker needs access to logs or other diagnostic output containing HTTP error exception messages. Exploitation does not require user interaction, but it does require the ability to view the exposed diagnostic data.
What can an attacker do with a disclosed restore password?
A plaintext PLC restore password could allow the attacker to perform unauthorized operations on the PLC.
How can teams determine whether they may be affected?
Check whether the application uses a version earlier than V3.3.62 and review application logs, exception stores, and diagnostic outputs for HTTP error messages that may contain PLC restore passwords.