CVE-2025-66327 is a race condition vulnerability classified under CWE-362, discovered in the network module of Huawei's HarmonyOS versions 5.0.1 and 5.1.0. The flaw arises from improper synchronization when multiple concurrent processes access shared resources, leading to unpredictable behavior. Specifically, the race condition can cause service disruption by interfering with the normal execution flow of network operations, potentially resulting in denial of service (DoS). The vulnerability's CVSS vector indicates local attack vector (AV:L), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), and scope change (S:C), with impact on availability (A:H) but no impact on confidentiality (C:N) or integrity (I:N). This means an attacker with local access to the device can exploit the race condition without needing elevated privileges or user interaction, causing a service outage or network module failure. Although no exploits are currently known in the wild, the vulnerability poses a significant risk to the stability of affected systems. The lack of available patches at the time of publication necessitates proactive mitigation strategies. The race condition's presence in the network module is critical because network services are essential for device communication and operation, and disruption can cascade into broader service interruptions.

For European organizations, the primary impact of CVE-2025-66327 is potential denial of service affecting devices running Huawei HarmonyOS 5.0.1 and 5.1.0. This can disrupt network connectivity and availability of services relying on these devices, particularly in environments where Huawei hardware and software are integrated into critical infrastructure or enterprise networks. Service outages could affect telecommunications providers, enterprises using Huawei-based IoT devices, and mobile operators with HarmonyOS-powered devices in their networks. Although confidentiality and integrity are not directly compromised, the availability impact can lead to operational downtime, loss of productivity, and potential cascading failures in dependent systems. Organizations in sectors such as telecommunications, manufacturing, and public services that utilize Huawei HarmonyOS devices may face increased risk. The local attack vector requirement limits remote exploitation but insider threats or compromised local access points could leverage this vulnerability. The absence of known exploits reduces immediate risk but does not eliminate the threat, especially as attackers may develop exploits post-disclosure.

1. Monitor Huawei’s official security advisories for patches addressing CVE-2025-66327 and apply them promptly once released. 2. Implement strict access controls to limit local access to devices running affected HarmonyOS versions, reducing the attack surface. 3. Employ network segmentation to isolate Huawei HarmonyOS devices from critical infrastructure to contain potential service disruptions. 4. Conduct thorough code reviews and concurrency testing in custom applications or modules interfacing with the network stack to detect and remediate synchronization issues. 5. Use runtime monitoring tools to detect abnormal process behavior indicative of race conditions or service instability. 6. Develop incident response plans that include procedures for rapid recovery from network service outages caused by such vulnerabilities. 7. Engage with Huawei support channels for guidance on interim mitigation techniques, such as configuration changes that may reduce concurrency risks. 8. Educate local administrators and users about the risks of local exploitation and enforce strict endpoint security policies to prevent unauthorized access.