Which versions of Jwt Attack are affected by EUVD-2026-22233?

Siemens SINEC NMS versions prior to V4.0 SP3 contain an authentication bypass vulnerability in the UMC component that allows unauthenticated remote attackers to gain unauthorized access to the…

How to fix or mitigate EUVD-2026-22233?

Within 24 hours: Identify and document all Siemens SINEC NMS installations with versions prior to V4.0 SP3, particularly those with UMC enabled and internet-facing access. Within 7 days: Implement network segmentation to restrict remote access to SINEC NMS systems to authorized management networks only; deploy enhanced monitoring on SINEC NMS authentication logs for anomalous access patterns. Within 30 days: Upgrade all affected systems to Siemens SINEC NMS V4.0 SP3 or later following vendor patch release and change management procedures; validate patch deployment and re-test access controls.

Jwt Attack EUVD-2026-22233

Q: What is the CVSS score of EUVD-2026-22233?

EUVD-2026-22233 has a CVSS 4.0 base score of 6.9 (Medium). CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/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. EPSS exploitation probability: 0.1%.

| CVE-2026-24032 MEDIUM

Improper Verification of Cryptographic Signature (CWE-347)

2026-04-14 siemens

GHSA-7f3f-wq83-6q76

Authentication Bypass Jwt Attack

6.9

CVSS 4.0 · NVD

Severity by source

NVD PRIMARY

6.9 MEDIUM

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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Lifecycle Timeline

Severity Changed

Apr 14, 2026 - 09:22 NVD

HIGH MEDIUM

CVSS changed

Apr 14, 2026 - 09:22 NVD

7.3 (HIGH) 6.9 (MEDIUM)

Analysis Generated

Apr 14, 2026 - 09:11 vuln.today

EUVD ID Assigned

Apr 14, 2026 - 09:00 euvd

EUVD-2026-22233

Analysis Generated

Apr 14, 2026 - 09:00 vuln.today

CVE Published

Apr 14, 2026 - 08:40 nvd

MEDIUM 6.9

DescriptionCVE.org

A vulnerability has been identified in SINEC NMS (All versions < V4.0 SP3 with UMC). The affected application contains an authentication weakness due to insufficient validation of user identity in the UMC component. This could allow an unauthenticated remote attacker to bypass authentication and gain unauthorized access to the application. (ZDI-CAN-27564)

AnalysisAI

Authentication bypass in Siemens SINEC NMS versions prior to V4.0 SP3 with UMC allows unauthenticated remote attackers to gain unauthorized access due to insufficient user identity validation in the UMC component (CWE-347: Improper Verification of Cryptographic Signature). The vulnerability enables network-based attacks with low complexity requiring no user interaction (CVSS 7.3, AV:N/AC:L/PR:N/UI:N), granting partial access to confidentiality, integrity, and availability. ZDI tracking ID CAN-27564 suggests coordinated disclosure. No active exploitation (CISA KEV) or public exploit code confirmed at time of analysis, though JWT-related authentication bypasses are well-understood attack primitives.

Technical ContextAI

The vulnerability resides in the User Management Console (UMC) component of Siemens SINEC Network Management System, an industrial network management platform. CWE-347 indicates improper verification of cryptographic signatures, commonly associated with JSON Web Token (JWT) implementation flaws. Typical JWT authentication bypass scenarios include algorithm confusion attacks (switching RS256 to HS256), signature stripping (accepting unsigned tokens), weak secret keys, or acceptance of self-signed tokens without proper validation. The SINEC NMS platform manages industrial Ethernet networks in operational technology environments, making authentication failures particularly critical as they expose network configuration, device management, and monitoring capabilities to unauthorized actors. The CPE identifier cpe:2.3:a:siemens:sinec_nms confirms all versions prior to the patched release are affected.

RemediationAI

Upgrade to Siemens SINEC NMS V4.0 SP3 or later, which addresses the authentication bypass vulnerability in the UMC component. Siemens ProductCERT advisory SSA-801704 available at https://cert-portal.siemens.com/productcert/html/ssa-801704.html provides official patch guidance and installation instructions. As interim mitigation measures until patching is feasible, restrict network access to SINEC NMS management interfaces using firewall rules limiting connectivity to trusted administrative networks only, disable UMC component if not operationally required, implement network segmentation isolating the management system from untrusted networks, and enable comprehensive logging to detect potential unauthorized access attempts. Organizations should prioritize patching for internet-facing or cross-zone accessible SINEC NMS deployments given the unauthenticated remote attack vector.