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CVE-2026-56451

CRITICAL 10 ALL-YEARS

Published 2026-07-14 · Last modified 2026-07-14 · siemens · NVD: Deferred

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.

ELEVATED IMPACT

Severe if exploited (CVSS 10), but no confirmed exploitation. Patch on a normal cadence.

Exploitation likelihood

0.3%chance of exploitation in 30 days · 23rd percentile

○ In CISA KEV○ Public exploit / PoC◆ SSVC: exploitation none, automatable yes

Impact if exploited

10CVSS 4.0 · CRITICAL · CNA

  • ConfidentialityHigh
  • IntegrityHigh
  • AvailabilityLow

What an attacker needs

  • ✓Access: Reachable over the network — no local access needed
  • ✓Privileges: No account or privileges required
  • ✓User interaction: No user interaction needed
  • ✓Complexity: No special conditions — reliably repeatable
  • ✓Requirements: No special attack requirements

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept & exploit code

No public exploit or proof-of-concept code is catalogued for this CVE (no ExploitDB, Nuclei, or CISA-KEV entry). It may still exist — search GitHub or check the references below.

Affected

Vendors Siemens

Products Opcenter X

Weakness (CWE)

  • CWE-347: : Improper Verification of Cryptographic Signature

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:L/SC:L/SI:H/SA:H

All CVSS metrics

  • CRITICAL 10 v3.1 · CNA Primary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
  • CRITICAL 10 v4.0 · CNA Primary
    CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:L/SC:L/SI:H/SA:H
  • CRITICAL 10 v4.0 · NVD Secondary
    CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:L/SC:L/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
  • CRITICAL 10 v3.1 · NVD Secondary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

References

Technical & other

Sources: NVD · CVE.org · EPSS