A null pointer dereference vulnerability in the airpig2011 IEC104 library allows unauthenticated attackers to cause a denial of service via a segmentation fault.

The flaw exists in the IEC10X_PrioEnQueue function, where concurrent thread enqueuing leads to the dereference of a null or freed pointer. This vulnerability is remotely exploitable by an unauthenticated attacker without requiring user interaction.

The exploitation of this vulnerability results in a denial of service, which can cause significant disruption to industrial control protocol communications relying on this library. With a CVSS score of 7.5, the risk is classified as High because it allows remote, unauthenticated attackers to crash services, potentially impacting operational availability and system reliability in environments where IEC104 is deployed.

Immediate Action: As no official patch is currently available, users should restrict network access to affected services or implement rate limiting to reduce the likelihood of triggering the race condition.

Proactive Monitoring: Monitor system logs for segmentation faults or unexpected service terminations that may indicate exploitation attempts.

Compensating Controls: Deploy network-level access controls to ensure only authorized traffic can reach the affected IEC104 interface, thereby limiting the exposure of the vulnerable function.

Public Exploit Available: Unknown.

Given the potential for service disruption, administrators should prioritize isolating systems utilizing the airpig2011 IEC104 library. Until a formal security patch is released by the maintainers, strict network segmentation is the most effective method to prevent unauthenticated attackers from triggering this denial of service condition.