Missing AuthenticationWeakness · CWE-306

CVE-2026-12819

CRITICAL · 9.3 CVSS v4.0 Published 2026-06-30
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click 7 weeks old

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Delta Electronics DVP12SE PLC exposes a Modbus TCP service over a specified port without authentication or access control, permitting unauthenticated interaction with security-sensitive PLC functions.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

The Delta Electronics DVP12SE PLC exposes a Modbus TCP service on a specified port without any authentication or access control mechanisms. This critical vulnerability allows any unauthenticated network attacker to directly interact with security-sensitive PLC functions, potentially enabling unauthorized control of industrial processes.

MitigationImplement network segmentation and firewall rules to isolate the PLC from untrusted networks, and apply vendor-provided security updates or configuration changes to enable authentication on the Modbus service.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
Authentication
X
User interaction
None
Scope
X

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify the device model
    Check the PLC's model number via its web interface, console, or network banner grab on common management ports. Look for 'DVP12SE' or Delta Electronics branding.
    Affected if The device is a Delta Electronics DVP12SE PLC
  2. Detect Modbus TCP service availability
    Perform a TCP port scan targeting ports 502 (standard Modbus) and any additional ports the PLC may use. Use 'nmap -p 502 <target>' or similar network scanner.
    Affected if Port 502 or the PLC's Modbus service port is open and responding
  3. Verify unauthenticated Modbus access
    Attempt a Modbus function code 0x04 (read input registers) or 0x03 (read holding registers) using a Modbus client (e.g., mbtget, modscan) without providing any credentials.
    Affected if Modbus queries return valid responses without authentication being required
  4. Check for authentication configuration
    If the PLC provides a configuration interface (web, serial, or management software), inspect the Modbus/TCP settings for any authentication or access control options. Look for 'authentication', 'access control', or 'security' settings.
    Affected if Authentication is disabled or not configurable for the Modbus service
  5. Confirm network exposure
    Review network firewall rules or access control lists to determine if the PLC's Modbus port is accessible from untrusted network segments or the internet.
    Affected if The Modbus TCP port is reachable from outside the trusted industrial network

A user is affected if they operate a Delta Electronics DVP12SE PLC with Modbus TCP exposed on the network and accessible without any authentication or access control.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Implement network segmentation and firewall rules to isolate the PLC from untrusted networks, and apply vendor-provided security updates or configuration changes to enable authentication on the Modbus service.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA3.0 h
21.0 hours of engineering $3,680
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,888.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2026-12819 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-12819 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data