CVE-2025-54636 is a medium-severity vulnerability identified in Huawei's HarmonyOS versions 3.0.0, 3.1.0, and 4.0.0. The root cause is improper input validation (CWE-20) within the kernel's drop detection module, which leads to a buffer overflow condition. Specifically, insufficient verification of incoming data allows an attacker with high privileges to trigger a buffer overflow, potentially causing the system to crash or become unresponsive, thereby impacting system availability. The vulnerability does not affect confidentiality or integrity, and no user interaction is required for exploitation. The CVSS v3.1 base score is 4.4, reflecting a local attack vector with low complexity but requiring high privileges. No known exploits are currently reported in the wild, and no patches have been linked yet. Given that the flaw resides in the kernel module, exploitation could lead to denial-of-service conditions, disrupting device operations that rely on HarmonyOS, particularly in embedded or IoT environments where Huawei's OS is deployed.

For European organizations, the primary impact of this vulnerability is on system availability. Devices running affected versions of HarmonyOS could be forced into denial-of-service states, potentially disrupting business operations, especially in sectors relying on Huawei's ecosystem such as telecommunications, smart devices, and IoT infrastructure. Given Huawei's significant presence in European telecommunications networks and consumer devices, an attack exploiting this vulnerability could lead to service outages or degraded performance. Although the vulnerability requires high privileges, insider threats or compromised administrative accounts could leverage this flaw to disrupt services. The lack of confidentiality or integrity impact reduces risks related to data breaches, but availability disruptions could affect critical infrastructure and services, leading to operational and reputational damage.

Organizations should prioritize upgrading affected HarmonyOS devices to patched versions once available from Huawei. Until patches are released, limiting administrative access to trusted personnel and enforcing strict privilege management can reduce exploitation risk. Monitoring kernel module behavior and system logs for anomalies related to the drop detection module may help detect attempted exploitation. Network segmentation to isolate critical HarmonyOS devices and applying host-based intrusion detection systems can further mitigate risk. Additionally, organizations should engage with Huawei support channels for timely updates and consider deploying redundancy and failover mechanisms to maintain service continuity in case of denial-of-service incidents.