CVE-2025-21476 is a high-severity buffer overflow vulnerability (CWE-120) affecting multiple Qualcomm Snapdragon chipsets and related wireless connectivity modules. The flaw arises from improper handling of input parameters during the handshake process with the Trusted Virtual Machine (TVM), leading to memory corruption. Specifically, the vulnerability occurs because the code copies input data into a buffer without verifying that the input size fits within the allocated buffer boundaries. This classic buffer overflow can result in overwriting adjacent memory, potentially allowing an attacker to execute arbitrary code, escalate privileges, or cause denial of service by crashing the system. The affected products include a broad range of Snapdragon SoCs (e.g., SM8550, SM8650, SM8750 series), connectivity chips (e.g., QCA6391, WCN series), and integrated modules used in smartphones, IoT devices, and embedded systems. The CVSS 3.1 score of 7.8 reflects the vulnerability's high impact on confidentiality, integrity, and availability, with low attack complexity and requiring only low privileges but no user interaction. Although no known exploits are currently reported in the wild, the vulnerability's nature and affected widespread hardware platforms make it a significant risk. The lack of publicly available patches at the time of publication underscores the urgency for affected vendors and integrators to prioritize mitigation and monitoring efforts.

For European organizations, the impact of CVE-2025-21476 can be substantial due to the widespread use of Qualcomm Snapdragon chipsets in mobile devices, embedded systems, and IoT infrastructure. Exploitation could allow attackers to compromise device security, leading to unauthorized access to sensitive data, disruption of critical services, or persistent footholds within corporate or industrial networks. In sectors such as telecommunications, manufacturing, healthcare, and critical infrastructure—where Snapdragon-based devices are commonly deployed—this vulnerability could facilitate espionage, sabotage, or ransomware attacks. The potential for privilege escalation and remote code execution increases the risk of large-scale compromise, especially in environments where devices are interconnected and trusted. Furthermore, the vulnerability's exploitation could undermine compliance with European data protection regulations (e.g., GDPR) due to data breaches or service outages. The absence of user interaction for exploitation means attacks could be automated and stealthy, increasing the threat to enterprise and governmental entities across Europe.

Given the absence of publicly released patches, European organizations should implement a multi-layered mitigation strategy. First, conduct an inventory to identify all devices using affected Qualcomm Snapdragon chipsets and wireless modules. Engage with device manufacturers and Qualcomm for timely patch updates and firmware upgrades. Until patches are available, apply network segmentation to isolate vulnerable devices, minimizing exposure to untrusted networks. Employ strict access controls and monitor for anomalous behavior indicative of exploitation attempts, such as unusual handshake failures or memory corruption events. Utilize endpoint detection and response (EDR) tools capable of detecting exploitation patterns related to buffer overflows. For mobile devices, enforce mobile device management (MDM) policies that restrict installation of untrusted applications and enforce timely OS and firmware updates. Additionally, consider deploying intrusion prevention systems (IPS) with signatures or heuristics targeting exploitation attempts of this vulnerability once available. Finally, educate security teams about this vulnerability to ensure rapid incident response if exploitation is suspected.