Which versions of Openplc V3 are affected by EUVD-2026-21035?

OpenPLC_V3 contains a critical authorization bypass in its REST API that allows any authenticated user to escalate privileges to administrator level or delete existing admin accounts, regardless of…

How to fix or mitigate EUVD-2026-21035?

Within 24 hours: Inventory all OpenPLC_V3 deployments and document current version numbers and user roles. Within 7 days: Implement network segmentation to restrict API access to trusted administrative networks only; disable or restrict REST API access where operationally feasible; audit and document all user accounts with admin privileges. Within 30 days: Monitor vendor advisories for patch availability; conduct security assessment of alternative ICS platforms if patch timeline extends beyond 60 days; implement compensating network-based access controls (WAF rules to block user management API endpoints from non-admin source IPs).

Openplc V3 EUVD-2026-21035

Q: What is the CVSS score of EUVD-2026-21035?

EUVD-2026-21035 has a CVSS 4.0 base score of 8.7 (High). CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/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: 0.0%.

| CVE-2026-35063 HIGH

Missing Authorization (CWE-862)

2026-04-09 icscert

Authentication Bypass Openplc V3

8.7

CVSS 4.0 · NVD

Severity by source

NVD PRIMARY

8.7 HIGH

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

Low

User Interaction

None

Scope

Lifecycle Timeline

Re-analysis Queued

Apr 16, 2026 - 20:52 vuln.today

cvss_changed

EUVD ID Assigned

Apr 09, 2026 - 19:45 euvd

EUVD-2026-21035

Analysis Generated

Apr 09, 2026 - 19:45 vuln.today

CVE Published

Apr 09, 2026 - 19:00 nvd

HIGH 8.7

DescriptionCVE.org

OpenPLC_V3 REST API endpoint checks for JWT presence but never verifies the caller's role. Any authenticated user with role=user can delete any other user, including administrators, by specifying their user ID or they can create new accounts with role=admin, escalating to full administrator access.

AnalysisAI

Authorization bypass in OpenPLC_V3 REST API allows authenticated low-privilege users to delete administrator accounts or create new admin-level accounts. The API validates JWT token presence but fails to enforce role-based access control, enabling any user with basic authentication to escalate privileges to full administrator access or remove existing administrators by manipulating user ID parameters. This affects all versions of OpenPLC_V3. No public exploit identified at time of analysis.

Technical ContextAI

CWE-862 missing authorization vulnerability. JWT authentication mechanism verifies token validity but omits role attribute validation in user management endpoints. Authenticated requests with role=user bypass intended RBAC enforcement, allowing unrestricted administrative operations including account creation with arbitrary role assignment and user deletion across privilege boundaries.

RemediationAI

No vendor-released patch identified at time of analysis. Recommended immediate actions: implement network segmentation to restrict REST API access to trusted administrative networks only; disable remote API access if not operationally required; enforce principle of least privilege by removing unnecessary user accounts with authentication credentials; monitor authentication logs for unauthorized user creation or deletion attempts. Organizations should review CISA advisory ICSA-25-345-10 for vendor coordination status and mitigation guidance: https://www.cisa.gov/news-events/ics-advisories/icsa-25-345-10. Consider deploying reverse proxy with mandatory role verification middleware until vendor releases patched version with proper RBAC enforcement.