CVE-2025-11783 Overview
CVE-2025-11783 is a stack-based buffer overflow vulnerability affecting Circutor SGE-PLC1000 and SGE-PLC50 programmable logic controllers running firmware version 9.0.2. The vulnerability exists in the AddEvent() function, which fails to perform proper boundary checking when copying user-controlled username input to a fixed-size buffer of 48 bytes. Successful exploitation of this flaw can lead to memory corruption and potentially enable remote code execution on affected industrial control systems.
This vulnerability is particularly concerning in industrial environments where PLC devices are critical components of operational technology (OT) infrastructure. Attackers with adjacent network access could leverage this flaw to compromise the integrity and availability of industrial control processes.
Critical Impact
Stack-based buffer overflow enabling memory corruption and potential remote code execution on industrial PLC devices with a CVSS score of 8.5 (HIGH).
Affected Products
- Circutor SGE-PLC1000 Firmware v9.0.2
- Circutor SGE-PLC1000 Hardware
- Circutor SGE-PLC50 Firmware v9.0.2
- Circutor SGE-PLC50 Hardware
Discovery Timeline
- 2025-12-02 - CVE-2025-11783 published to NVD
- 2025-12-03 - Last updated in NVD database
Technical Details for CVE-2025-11783
Vulnerability Analysis
The vulnerability is classified as CWE-121 (Stack-based Buffer Overflow), a critical memory corruption issue that occurs when data written to a buffer exceeds its allocated size on the stack. In this case, the AddEvent() function in the Circutor SGE-PLC firmware accepts user-controlled username input without validating its length against the destination buffer's capacity.
The CVSS 4.0 vector for this vulnerability is CVSS:4.0/AV:A/AC:L/AT:N/PR:L/UI:N/VC:H/VI:L/VA:H/SC:H/SI:L/SA:H/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, indicating:
- Attack Vector: Adjacent Network - requires network adjacency to the target
- Attack Complexity: Low - no specialized conditions required
- Privileges Required: Low - basic user authentication needed
- User Interaction: None - can be exploited without user action
The EPSS (Exploit Prediction Scoring System) data indicates a probability of 0.208% with a percentile ranking of 43.317 as of 2025-12-16, suggesting moderate exploitation likelihood in the wild.
Root Cause
The root cause of this vulnerability lies in the unsafe handling of user-supplied input within the AddEvent() function. The function allocates a fixed 48-byte buffer on the stack for storing username data but fails to implement proper bounds checking before copying the input. When a username exceeding 48 bytes is provided, the excess data overwrites adjacent memory locations on the stack, including potentially critical data such as return addresses and saved frame pointers.
This is a classic example of unsafe string handling in embedded firmware, where memory constraints often lead developers to use fixed-size buffers without implementing corresponding length validation mechanisms.
Attack Vector
The attack requires adjacent network access, meaning an attacker must be on the same network segment as the target PLC device. With low-privilege credentials (basic authentication), an attacker can submit a maliciously crafted username input to the vulnerable AddEvent() function. By carefully constructing the overflow payload, an attacker can:
- Overwrite the saved return address on the stack
- Redirect program execution to attacker-controlled code
- Achieve remote code execution in the context of the PLC firmware
The vulnerability does not require any user interaction and has high impact on confidentiality and availability, with potential to affect subsequent systems connected to the compromised PLC.
Detection Methods for CVE-2025-11783
Indicators of Compromise
- Abnormal network traffic to PLC devices on the adjacent network containing oversized username fields
- Unexpected process crashes or restarts on SGE-PLC1000 or SGE-PLC50 devices
- Suspicious authentication attempts with unusually long username strings (exceeding 48 bytes)
- Memory access violations or stack corruption errors in device logs
- Unauthorized configuration changes or unexpected behavior in PLC-controlled systems
Detection Strategies
Organizations should implement network-based detection to identify potential exploitation attempts:
- Network Traffic Analysis: Monitor for HTTP/API requests to PLC devices containing username parameters exceeding 48 characters
- Anomaly Detection: Establish baseline behavior for PLC communication patterns and alert on deviations
- ICS/SCADA Monitoring: Deploy industrial control system-specific monitoring solutions that understand PLC protocols
- Log Analysis: Aggregate and analyze logs from PLC devices for authentication anomalies
SentinelOne Singularity™ Platform provides comprehensive visibility into OT environments, enabling detection of anomalous behavior patterns that may indicate exploitation attempts against industrial control systems.
Monitoring Recommendations
- Implement network segmentation to isolate PLC devices from general network traffic
- Deploy intrusion detection systems (IDS) at network boundaries adjacent to ICS/SCADA environments
- Enable verbose logging on PLC devices where supported and forward logs to a centralized SIEM
- Establish alerting thresholds for authentication failures and anomalous input patterns
- Conduct regular vulnerability scans of OT infrastructure to identify unpatched devices
How to Mitigate CVE-2025-11783
Immediate Actions Required
- Identify all Circutor SGE-PLC1000 and SGE-PLC50 devices running firmware version 9.0.2 in your environment
- Implement strict network segmentation to isolate affected PLC devices from untrusted network segments
- Apply firewall rules to restrict access to PLC devices from authorized management stations only
- Monitor affected devices for signs of exploitation or anomalous behavior
- Review and strengthen authentication mechanisms for PLC access
- Contact Circutor for information about available security patches
Patch Information
Organizations should consult the INCIBE-CERT security advisory for detailed remediation guidance: https://www.incibe.es/en/incibe-cert/notices/aviso-sci/multiple-vulnerabilities-circutor-products-0
Contact Circutor directly for firmware update availability and patch deployment procedures. Until patches are applied, prioritize network-level mitigations to reduce exposure.
Workarounds
If patching is not immediately possible, implement the following compensating controls:
- Network Isolation: Place affected PLC devices on dedicated VLAN segments with strict access controls
- Access Control Lists: Implement ACLs to limit communication to only authorized IP addresses
- Input Validation: Where possible, implement additional validation layers at network perimeter devices
- Monitoring Enhancement: Increase monitoring intensity for affected device segments
- Physical Security: Ensure physical access to PLC devices and their network infrastructure is restricted
Network segmentation example for isolating industrial control systems:
# Example firewall rules to restrict PLC access
# Deny all traffic to PLC network by default
# Allow only authorized management stations
# Enable logging for audit purposes
Organizations should work with their OT security teams and Circutor support to develop a comprehensive remediation plan that minimizes operational disruption while addressing this vulnerability.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
