CVE-2025-2962 is a high-severity denial-of-service (DoS) vulnerability identified in the DNS implementation of the Zephyr real-time operating system (RTOS). The flaw arises from a loop construct within the DNS code that contains an unreachable exit condition, effectively causing an infinite loop when triggered. This infinite loop results in the affected system becoming unresponsive or stuck, leading to a denial of service. Zephyr is widely used in embedded systems and Internet of Things (IoT) devices due to its lightweight and modular design. The vulnerability affects all versions of Zephyr, indicating a systemic issue in the DNS handling code. The CVSS v3.1 base score of 8.2 reflects the high impact of this vulnerability, with an attack vector of network (AV:N), low attack complexity (AC:L), no privileges required (PR:N), and no user interaction needed (UI:N). The scope is unchanged (S:U), and the impact is solely on availability (A:H), with no confidentiality or integrity impact. Exploitation involves sending specially crafted DNS packets to a device running Zephyr, causing it to enter an infinite loop and become unavailable. No known exploits are currently reported in the wild, and no patches or mitigation links are provided yet, suggesting this is a newly disclosed vulnerability. Given Zephyr’s deployment in critical embedded and IoT environments, this vulnerability poses a significant risk to device availability and operational continuity.

For European organizations, the impact of CVE-2025-2962 can be substantial, particularly for industries relying on embedded systems and IoT devices running Zephyr RTOS. This includes sectors such as industrial automation, smart energy grids, automotive systems, healthcare devices, and telecommunications infrastructure. A successful exploitation could lead to device outages, disrupting critical services and operational processes. Since the vulnerability causes a denial of service without compromising confidentiality or integrity, the primary risk is operational downtime and potential cascading effects on dependent systems. In industrial environments, this could halt manufacturing lines or critical monitoring systems. In smart city or energy applications, it could disrupt essential services. The lack of required privileges or user interaction means attackers can remotely trigger the vulnerability over the network, increasing the risk of widespread exploitation. European organizations with extensive IoT deployments or embedded device usage must consider this vulnerability a high operational risk, especially in environments where device availability is critical for safety or regulatory compliance.

1. Immediate mitigation should focus on network-level controls: implement strict ingress filtering and firewall rules to restrict unsolicited DNS traffic to devices running Zephyr. 2. Deploy network anomaly detection systems to identify unusual DNS traffic patterns that could trigger the infinite loop. 3. Isolate critical Zephyr-based devices on segmented networks with limited exposure to external or untrusted networks. 4. Monitor vendor communications closely for official patches or updates addressing this vulnerability and prioritize rapid deployment once available. 5. Where possible, implement watchdog timers or hardware reset mechanisms on embedded devices to recover from infinite loop conditions automatically. 6. Conduct an inventory of all devices running Zephyr RTOS within the organization to assess exposure and prioritize risk management. 7. Engage with device manufacturers or integrators to confirm if custom firmware updates or mitigations are planned or available. 8. Consider temporary disabling or limiting DNS functionality on affected devices if feasible without impacting critical operations until patches are applied.