CVE-2026-56451

JWT Algorithm Validation Bypass in Siemens Opcenter X

Published Jul 14, 2026 CVSS 4.0 · 10 Critical EPSS < 1% KEV · Not listed
Description
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.

Analysis

AI-generated

Technical impact

A flaw in Opcenter X allows an attacker to the platform accepts without validating the signing algorithm. The result is a complete compromise of authentication controls: anyone can impersonate any user, including administrators, and gain unrestricted access to the application. The vulnerability is classified as CWE‑347 and provides an unconditional path to bypass security checks.

Affected Systems

The issue affects all releases of Siemens Opcenter X prior to version V2604. Users running any of those older versions are vulnerable.

Risk and Exploitability

The CVSS score of 10 indicates catastrophic impact if exploited. Although the EPSS score is below 1%—a low probability of exploitation in the wild—the flaw remains highly dangerous because the attack is remote, unauthenticated, and can be executed from any network location. It is not listed in the CISA KEV catalog, but the severity and the potential for full account takeover demand urgent attention.

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

  • Restrict the JWT issuance endpoint so only authenticated users can acquire tokens, or disable JWT usage entirely.
  • Enforce strong, asymmetric signing algorithms such as RS256 with proper key verification in the application.
  • Enable multi‑factor authentication for all users where supported to add an additional layer of protection.
  • Verify the installed version is older than V2604, consult Siemens for any available update, and, if no patch is released, consider migration or additional network segmentation to limit exposure.

Generated by OpenCVE AI on July 31, 2026 at 10:36 UTC.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Siemens
Siemens opcenter X
Vendors & Products Siemens
Siemens opcenter X
Type Values Removed Values Added
Title JWT Algorithm Validation Bypass in Siemens Opcenter X
Type Values Removed Values Added
Title JWT Algorithm Validation Bypass in Siemens Opcenter X
Type Values Removed Values Added
Title JWT Algorithm Validation Bypass in Siemens Opcenter X
Type Values Removed Values Added
Title JWT Algorithm Validation Failure Enables Full Account Takeover in Siemens Opcenter X
Type Values Removed Values Added
Title JWT Algorithm Validation Failure Enables Full Account Takeover in Siemens Opcenter X
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description 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.
Weaknesses CWE-347
References
Metrics cvssV3_1

{'score': 10, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H'}

cvssV4_0

{'score': 10, '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'}

Weaknesses
  • CWE-347

    Improper Verification of Cryptographic Signature

Sources

Status
PUBLISHED
Assigner
siemens
Published
Updated
Jul 14, 2026, 2:30 PM
Reserved
Jun 22, 2026, 1:17 PM
Status
Deferred
Published
Jul 14, 2026, 10:16 AM
Modified
Oct 23, 2026, 11:10 PM