CVE-2024-36843 in libmodbus
Summary
by MITRE • 05/31/2024
libmodbus v3.1.6 was discovered to contain a heap overflow via the modbus_mapping_free() function.
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Analysis
by VulDB Data Team • 05/01/2025
The vulnerability identified as CVE-2024-36843 affects libmodbus version 3.1.6 and represents a critical heap overflow condition within the modbus_mapping_free() function. This issue arises from improper memory management during the cleanup process of modbus mapping structures, creating a potential avenue for arbitrary code execution or system instability. The vulnerability demonstrates a classic memory safety issue that can be exploited by attackers who can influence the modbus mapping data structures during program execution. The heap overflow occurs when the function attempts to free memory blocks without proper validation of the mapping structure integrity, leading to unpredictable behavior in the affected applications.
The technical flaw manifests when the modbus_mapping_free() function processes mapping data that has been corrupted or improperly initialized, causing the heap allocator to write beyond allocated memory boundaries. This condition can be triggered through malformed modbus requests or by manipulating the internal state of the modbus mapping structures. The vulnerability falls under CWE-121 heap-based buffer overflow, which is classified as a high-risk issue due to the potential for remote code execution. The flaw is particularly concerning in industrial control systems and SCADA environments where libmodbus is commonly deployed, as these systems often process untrusted network data without adequate input validation.
The operational impact of this vulnerability extends beyond simple memory corruption, potentially allowing attackers to execute arbitrary code on affected systems or cause denial of service conditions. In environments where libmodbus is used for communication between industrial devices and control systems, an attacker could exploit this vulnerability to gain unauthorized access to critical infrastructure components. The exploitability of this issue increases when the affected applications process modbus data from external sources without proper sanitization, making it particularly dangerous in networked environments. The vulnerability affects systems that rely on the modbus protocol for industrial automation and monitoring, where the stability and security of the communication layer is paramount.
Organizations should prioritize immediate remediation by upgrading to libmodbus version 3.1.7 or later, which contains the necessary patches to address the heap overflow condition. System administrators should also implement network segmentation and access controls to limit exposure to potentially malicious modbus traffic. Additional mitigations include input validation at network boundaries, monitoring for unusual modbus traffic patterns, and implementing intrusion detection systems to identify potential exploitation attempts. The vulnerability aligns with ATT&CK technique T1059.007 for command and script injection, as exploitation could enable attackers to execute arbitrary commands on affected systems. Security teams should conduct thorough vulnerability assessments of all systems using libmodbus to identify potential exposure and implement comprehensive monitoring to detect exploitation attempts.