Full Report
Opcenter X before V2604 contain an authentication bypass vulnerability that could allow an attacker to gain full unauthorized access to the application. Siemens has released a new version for Opcenter X and recommends to update to the latest version.
Analysis Summary
# Vulnerability: Authentication Bypass in Siemens Opcenter X
## CVE Details
- **CVE ID:** CVE-2026-56451
- **CVSS Score:** 10.0 (Critical)
- **CWE:** CWE-347: Improper Verification of Cryptographic Signature
## Affected Systems
- **Products:** Opcenter X
- **Versions:** All versions prior to V2604
- **Configurations:** Default installations utilizing JSON Web Token (JWT) based authentication.
## Vulnerability Description
The affected application fails to properly validate the algorithm specified in the JSON Web Token (JWT) header. In a JWT-based authentication system, this typically indicates that the application might accept tokens signed with a "none" algorithm or allow the substitution of asymmetric keys with symmetric keys (HS256 vs RS256). This flaw allows an unauthenticated remote attacker to forge arbitrary tokens, bypass security checks, and impersonate any user, including high-privilege administrative accounts.
## Exploitation
- **Status:** Information based on vendor advisory; no public PoC currently cited in the advisory.
- **Complexity:** Low
- **Attack Vector:** Network (Remote)
## Impact
- **Confidentiality:** High (Full unauthorized access to application data)
- **Integrity:** High (Ability to modify application settings and data)
- **Availability:** High (Potential for full administrative control leading to service disruption)
## Remediation
### Patches
- **Update to V2604 or later:** Siemens has released a corrected version. Software can be obtained via the Siemens Support Center: hxxps[://]support[.]sw[.]siemens[.]com/product/206159703/
### Workarounds
- **Network Segmentation:** Protect network access to affected devices with firewalls and VPNs to limit exposure to trusted traffic 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:** Monitor for unusual administrative logins or sessions originating from unexpected IP addresses.
- **Detection methods and tools:** Audit application logs for JWTs that utilize the "none" algorithm or mismatched cryptographic headers if such logging is available. Review user activity logs for unauthorized changes to system configurations.
## References
- **Siemens Security Advisory SSA-096828:** hxxps[://]cert-portal[.]siemens[.]com/productcert/pdf/ssa-096828[.]pdf
- **Siemens Industrial Security Home:** hxxps[://]www[.]siemens[.]com/industrialsecurity