CVE-2025-50518 is a use-after-free vulnerability identified in the libcoap library, specifically within the coap_delete_pdu_lkd function in the coap_pdu.c source file. Libcoap is an open-source implementation of the Constrained Application Protocol (CoAP), which is widely used in Internet of Things (IoT) environments and constrained networks for resource-constrained devices. The vulnerability arises from improper memory management after a Protocol Data Unit (PDU) object has been freed. When the coap_delete_pdu_lkd function attempts to access or manipulate memory that has already been released, it can lead to memory corruption. This corruption can potentially be exploited by an attacker to execute arbitrary code or cause a denial of service (DoS) by crashing the application using libcoap. Although the affected versions are not specified, the vulnerability is critical because use-after-free bugs are often exploitable remotely, especially if the vulnerable function processes network data. No patches or known exploits are currently reported, but the presence of this vulnerability in a widely used IoT protocol library suggests a significant risk if left unmitigated. The lack of a CVSS score indicates that the vulnerability is newly published and may require further analysis to fully understand its exploitability and impact scope.

For European organizations, the impact of CVE-2025-50518 can be substantial, particularly those involved in IoT deployments, smart city infrastructure, industrial automation, and critical infrastructure sectors that rely on CoAP for device communication. Exploitation could allow attackers to execute arbitrary code on devices running vulnerable versions of libcoap, potentially leading to unauthorized control, data exfiltration, or disruption of services. This is especially concerning for sectors such as energy, manufacturing, healthcare, and transportation, where IoT devices are integral to operational technology (OT) environments. Memory corruption vulnerabilities can also be leveraged to pivot into internal networks, increasing the risk of broader compromise. Given the increasing adoption of IoT technologies across Europe, the vulnerability could affect a wide range of devices and systems, amplifying the potential impact on confidentiality, integrity, and availability of critical services.

Organizations should first identify all assets using libcoap, particularly those exposed to untrusted networks or processing external CoAP messages. Since no patches are currently available, immediate mitigation steps include implementing network-level protections such as strict firewall rules, segmentation of IoT networks, and intrusion detection systems tuned to detect anomalous CoAP traffic patterns. Developers and vendors using libcoap should prioritize updating to patched versions once released and conduct thorough code reviews focusing on memory management in the coap_delete_pdu_lkd function. Employing runtime protections like AddressSanitizer during development and testing can help detect use-after-free issues. Additionally, applying strict input validation and limiting the exposure of CoAP services to trusted networks can reduce exploitation risk. Monitoring vendor advisories and subscribing to vulnerability feeds for updates on patches or exploit reports is essential for timely response.