Improper signature verification in Siemens Opcenter X
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- High · High · Low
- Fix status
- Fixed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-347.
Summary
A vulnerability has been identified in Opcenter X (All versions < V2604). Affected applications do not properly validate the algorithm specified in the JSON Web Token (JWT) header. This could allow an unauthenticated remote attacker to forge arbitrary JWT, bypass authentication mechanisms and impersonate any user including administrative accounts, potentially gaining full unauthorized access to the application.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
- Fix · CNA Opcenter X (Siemens) Fixed in V2604
Timeline
- 2026-10-02 Threatist record created from CVE-2026-56451
- 2026-10-03 Alias added: GHSA-j4h7-9cc4-7f3r
References
More Siemens vulnerabilities
- TI-2026-20057 Authentication bypass in Fortinet FortiWeb KEVCVSS 3.1CRITICAL 9.4
- TI-2025-26358 tls: fix handling of zero-length records on the rx_list KEVCVSS 3.1CRITICAL 9.8
- TI-2025-18911 Heap-based buffer overflow in Fortinet FortiSwitchManager KEVCVSS 3.1CRITICAL 9.8
- TI-2025-09686 Type confusion in Google Chrome KEVCVSS 3.1CRITICAL 9.8
- TI-2022-07142 Code injection in Spring Framework KEVCVSS 3.1CRITICAL 9.8
- TI-2021-19919 Apache Log4j2 JNDI features do not protect against attacker controlled LDAP and other JNDI related endpoints KEVCVSS 3.1CRITICAL 10.0
Sources
- CVE-2026-56451 · CVE Program
- CVE-2026-56451 · NVD
- FIRST EPSS
- GHSA-j4h7-9cc4-7f3r · GitHub Advisory Database · CC BY 4.0
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