CVE-2026-12577 Overview
CVE-2026-12577 affects the Delta Electronics DVP80ES3 programmable logic controller (PLC). The flaw is an improperly implemented security check for a standard [CWE-358], which allows a remote attacker to reach an availability-impacting condition over the network without authentication or user interaction. The vulnerability is tracked alongside CVE-2026-12575 and CVE-2026-12576 in the same Delta advisory covering multiple issues in DVP80ES3.
Critical Impact
An unauthenticated remote attacker can trigger a high availability impact against the DVP80ES3 controller, disrupting industrial processes that depend on the device.
Affected Products
- Delta Electronics DVP80ES3 programmable logic controller
- Refer to the Delta Vulnerability Report for specific firmware versions
- Industrial control system deployments using DVP80ES3 for automation logic
Discovery Timeline
- 2026-07-01 - CVE-2026-12577 published to NVD
- 2026-07-01 - Last updated in NVD database
Technical Details for CVE-2026-12577
Vulnerability Analysis
The DVP80ES3 controller implements a security check that does not correctly enforce the standard it was designed to satisfy. The check fails to reject conditions or inputs that a compliant implementation would reject. An attacker who understands the deviation can craft network traffic that bypasses the intended protection and reaches internal handling logic.
The resulting condition impacts availability of the controller. Confidentiality and integrity are not affected according to the advisory, but the loss of availability on a PLC can halt physical processes, stop production lines, or force safe-state transitions in connected equipment. Exploitation requires only network reachability to the controller.
Root Cause
The root cause is classified under [CWE-358] Improperly Implemented Security Check for Standard. The controller executes a validation routine that diverges from the reference standard, leaving edge cases unhandled. A conforming check would refuse the malicious input, but the DVP80ES3 implementation accepts or misroutes it, leading to the availability impact.
Attack Vector
The attack vector is network-based with low attack complexity. No privileges and no user interaction are required. An attacker with routable access to the PLC's control protocol port can send crafted requests directly to the device. In flat operational technology (OT) networks or where engineering workstations share segments with the controller, the exposure is direct.
No verified public exploit code is available for CVE-2026-12577 at the time of publication. Technical details are described in the vendor advisory linked in the references.
Detection Methods for CVE-2026-12577
Indicators of Compromise
- Unexpected reboots, watchdog resets, or communication timeouts on DVP80ES3 controllers
- Loss of cyclic scan updates to supervisory control and data acquisition (SCADA) or human-machine interface (HMI) systems
- Malformed or non-standard protocol frames directed at the PLC's control port from non-engineering hosts
- Repeated connection attempts from unknown source addresses targeting the DVP80ES3 management protocol
Detection Strategies
- Deploy an OT-aware intrusion detection system (IDS) with signatures for Delta DVP protocol anomalies
- Baseline normal engineering traffic to the PLC and alert on protocol deviations or unauthorized clients
- Correlate PLC availability events with network packet captures to identify the triggering request pattern
Monitoring Recommendations
- Log all sessions initiated to DVP80ES3 management and control ports and forward them to a central SIEM
- Monitor PLC health metrics such as CPU state, scan time, and communication status for sudden degradation
- Alert on any source outside the approved engineering workstation list contacting the controller
How to Mitigate CVE-2026-12577
Immediate Actions Required
- Restrict network access to DVP80ES3 controllers so only authorized engineering workstations can reach them
- Place affected PLCs behind an industrial firewall enforcing protocol-level filtering
- Review the Delta advisory Delta-PCSA-2026-00009 and identify all DVP80ES3 assets in scope
- Prepare a maintenance window to apply vendor firmware updates once released
Patch Information
Refer to Delta Electronics advisory Delta-PCSA-2026-00009 for firmware update availability and installation instructions. Apply the fixed firmware version specified by Delta to all affected DVP80ES3 controllers. Validate device operation in a staging environment before production rollout.
Workarounds
- Segment OT networks and block untrusted traffic to PLC control ports at the perimeter
- Require virtual private network (VPN) access with multi-factor authentication for any remote engineering session
- Disable unused network services on the controller where the firmware permits
- Continuously monitor controller availability and network traffic for anomalies until patched
# Configuration example - restrict access to DVP80ES3 at the network layer
# Allow only the engineering workstation subnet to reach the PLC
iptables -A FORWARD -s 10.10.20.0/24 -d 10.20.30.40 -p tcp --dport 502 -j ACCEPT
iptables -A FORWARD -d 10.20.30.40 -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
