CVE-2023-6448: Unitronics Vision PLC and HMI

Should you act?

Exploited: patch now if you run it

CISA has confirmed exploitation in the wild. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

Yes, if you run Unitronics Vision PLC and HMI. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2023-12-11, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2023-12-18; treat that as the outer limit, not the target.
EPSS 2.1%, percentile 81: FIRST’s model estimates a 2.1% chance of exploitation activity in the next 30 days, higher than 81% of all scored CVEs (elevated). EPSS is a probability, not a verdict.
Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.

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.

CISA’s summary

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

Weakness type: CWE-1188.

Product: Unitronics Vision PLC and HMI · Assigned by: cisa-cg · Published: 2023-12-05

Affected and fixed versions

Vendor	Product	Affected versions (per CVE record)
Unitronics	VisiLogic	< 9.9.00

Severity scores

Scored by	CVSS	Score	Vector
cisa-cg	3.1	9.8 Critical	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`

Attack vector: network (remotely reachable)
Attack complexity: low
Privileges required: none (no login)
User interaction: none
Scope: unchanged

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

CISA KEV: added 2023-12-11; federal due date 2023-12-18. Known ransomware use: Unknown.
CISA required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
CISA SSVC assessment: exploitation active, automatable yes, technical impact total.
FIRST EPSS (model of 2026-10-21): 2.09% probability of exploitation activity in the next 30 days; percentile 81.