AC500 V3 Multiple vulnerabilities
Plan PatchCVSS 8.33ADR011524Feb 24, 2026
ABB
Attack path
Attack VectorNetwork
Auth RequiredLow
ComplexityLow
User InteractionNone needed
Summary
ABB AC500 V3 PLC contains multiple vulnerabilities in versions prior to 3.9.0. The vulnerabilities allow an authenticated attacker to bypass user management controls (CVE-2025-2595), read and write security certificates and keys (CVE-2025-41659), or cause denial-of-service by exhausting controller resources (CVE-2025-41691). The affected versions are AC500 V3 firmware below 3.9.0.
What this means
What could happen
An attacker with engineering credentials could bypass user management to read process visualization files, modify security certificates, or crash the controller, disrupting plant operations and compromising system integrity.
Who's at risk
AC500 V3 PLC operators and engineering teams at utilities, manufacturing facilities, and water authorities who use this controller for process automation and safety logic. Any organization deploying AC500 V3 as a primary control device is affected.
How it could be exploited
An attacker with valid engineering workstation credentials connects to the AC500 V3 controller over the network and exploits improper access controls to read visualization files, modify security certificates and keys, or trigger resource exhaustion leading to controller restart.
Prerequisites
- Network access to the AC500 V3 controller
- Valid engineering workstation credentials or user account
remotely exploitablerequires authenticationlow complexityaffects controller availabilitycould compromise system integrity through certificate manipulation
Exploitability
Unlikely to be exploited — EPSS score 0.2%
Affected products (1)
ProductAffected VersionsFix Status
AC500 V3 <3.9.0<3.9.03.9.0
Remediation & Mitigation
0/3
Do now
0/1HARDENINGRestrict network access to the AC500 V3 controller to authorized engineering workstations only using firewall rules
Schedule — requires maintenance window
0/1Patching may require device reboot — plan for process interruption
HOTFIXUpdate AC500 V3 firmware to version 3.9.0 or later
Long-term hardening
0/1HARDENINGReview and audit user access permissions on the AC500 V3 controller to ensure least-privilege principle
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