CVE-2025-54620 is a deserialization vulnerability classified under CWE-502 affecting Huawei's HarmonyOS versions 5.0.1 and 5.1.0. The vulnerability resides in the 'ability module' of HarmonyOS, where untrusted data is deserialized without proper validation or sanitization. Deserialization vulnerabilities occur when an application deserializes data from untrusted sources, potentially allowing attackers to manipulate the serialized data to execute unintended code or cause denial of service. In this specific case, the impact is primarily on availability, indicating that exploitation could lead to system crashes or service interruptions rather than confidentiality or integrity breaches. The CVSS 3.1 base score is 5.5 (medium severity), with vector AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H, meaning the attack requires local access, low complexity, low privileges, no user interaction, and affects availability only. No known exploits are currently reported in the wild, and no patches have been linked yet. The vulnerability was published on August 6, 2025, shortly after being reserved on July 28, 2025. Given the nature of HarmonyOS as an operating system primarily for Huawei devices, this vulnerability could affect a wide range of IoT devices, smartphones, and embedded systems running these versions. The lack of confidentiality or integrity impact suggests the threat is limited to denial-of-service style attacks, potentially disrupting device functionality or availability of services dependent on the ability module.

For European organizations using Huawei devices running HarmonyOS 5.0.1 or 5.1.0, this vulnerability could lead to service disruptions or device unavailability. This is particularly critical for sectors relying on Huawei IoT devices or embedded systems in operational technology environments, such as manufacturing, smart city infrastructure, or telecommunications. The requirement for local access and low privileges means that attackers would need some form of access to the device, which could be achieved through insider threats or lateral movement after initial compromise. The denial of service impact could interrupt business operations, degrade user experience, or cause downtime in critical systems. While the vulnerability does not allow data theft or manipulation, availability issues can still have significant operational and financial consequences. European organizations with Huawei-based infrastructure should be aware of potential risks to device stability and plan accordingly.

1. Restrict local access to devices running affected HarmonyOS versions by enforcing strict physical and network access controls to prevent unauthorized users from reaching the ability module. 2. Monitor and audit device logs for unusual behavior or crashes related to the ability module to detect potential exploitation attempts early. 3. Implement network segmentation to isolate Huawei devices from critical infrastructure to limit the impact of any denial of service. 4. Apply principle of least privilege to users and processes interacting with the ability module to reduce the risk of exploitation. 5. Engage with Huawei support channels to obtain patches or updates as soon as they become available and plan timely deployment. 6. Consider deploying endpoint detection and response (EDR) solutions capable of identifying anomalous deserialization activities or crashes. 7. For critical environments, evaluate the feasibility of temporarily disabling or restricting functionality of the ability module if possible, until patches are applied.