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Actively exploited

CVE-2023-6448 Unitronics Vision PLC and HMI Insecure Default Password Vulnerability

Unitronics Vision Series PLCs and HMIs ship with an insecure default password, which if left unchanged, can allow attackers to execute remote commands.

From the CISA KEV catalogue version 2026.11.06, with Cybergen analysis. Updated 6 Nov 2026.

Our Assessment

Should You Worry?

Patch nowCybergen assessment
  • CISA confirmed exploitation in the wild and added it to the Known Exploited Vulnerabilities catalogue on 11 Dec 2023.
  • Rated Critical severity (CVSS 9.8, scored by Vendor).
  • It has been in the catalogue for 1,061 days. Systems still unpatched now have almost certainly been scanned for it.
The Vulnerability

What It Is

Unitronics VisiLogic before version 9.9.00, used in Vision and Samba PLCs and HMIs, uses a default administrative password. An unauthenticated attacker with network access can take administrative control of a vulnerable system.

Affected Versions

ProductVersions
Unitronics VisiLogicbefore 9.9.00

From the public CVE record, as supplied by the vendor. Always confirm against the vendor advisory.

From Watch to Action

What To Do Now

  1. 1

    Find it

    Search your asset inventory and external attack surface for Unitronics Vision PLC and HMI. Include cloud images, appliances and anything a supplier runs for you.

    Attack Surface Management
  2. 2

    Fix it

    Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

    Vulnerability Management
  3. 3

    Hunt for compromise

    If an affected system was reachable before you patched, assume it may have been hit. Check logs, new accounts, web shells and outbound connections from the date of exposure.

    Incident Response
  4. 4

    Prove it is fixed

    Rescan or test the system after patching. Upgrades that fail silently and forgotten secondary instances are common.

    Penetration Testing

Vendor Advisories

Regulation

The Compliance Clock

Cyber EssentialsRated critical, so if it affects devices in your Cyber Essentials scope, the update must be installed within 14 days of the vendor releasing it.NIS2If exploitation causes a significant incident, essential and important entities owe their CSIRT an early warning within 24 hours and a notification within 72 hours.DORAFinancial entities must classify ICT incidents and send an initial notification for a major incident within strict deadlines, with exploited flaws a common cause.US federal (BOD 22-01)Federal civilian agencies had until 18 Dec 2023 to remediate. A sensible benchmark for everyone else.

General guidance, not legal advice. Your obligations depend on your sector, scope and jurisdiction.

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Evidence

Sources

  1. CISA Known Exploited Vulnerabilities catalogue
  2. NVD: CVE-2023-6448
  3. CVE record: CVE-2023-6448
  4. FIRST EPSS
  5. cisa.gov/news-events/alerts/2023/11/28/exploitation-unitronics-plcs-used-water-and-wastewater-system
  6. unitronicsplc.com/cyber_security_vision-samba/
  7. downloads.unitronicsplc.com/Sites/plc/Visilogic/Version_Changes-Bug_Reports/VisiLogic%209.9.00%20Ver
  8. downloads.unitronicsplc.com/Sites/plc/Technical_Library/Unitronics-Cybersecurity-Advisory-2023-001-C