CVE-2025-21452 is a high-severity vulnerability identified in multiple Qualcomm Snapdragon platforms and associated wireless connectivity chipsets. The root cause is a reachable assertion failure (CWE-617) triggered during the processing of a random-access response (RAR) with an invalid Protocol Data Unit (PDU) length on LTE networks. This assertion failure leads to a transient denial-of-service (DoS) condition. Specifically, when the affected Snapdragon modem or wireless chipset receives a malformed RAR message containing an invalid PDU length, it triggers an assertion that causes the modem to crash or reset temporarily, disrupting normal device operation. The vulnerability affects a broad range of Qualcomm products, including numerous Snapdragon mobile platforms (from Snapdragon 315 5G IoT Modem through Snapdragon 888+ 5G Mobile Platform), FastConnect wireless subsystems, various QCA and WCN wireless chipsets, and Snapdragon automotive and XR platforms. The CVSS v3.1 base score is 7.5, reflecting a high severity due to network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:N), and no user interaction (UI:N). The impact is limited to availability (A:H), with no confidentiality or integrity impact. No known exploits are currently reported in the wild, and no patches have been linked yet. The vulnerability is exploitable remotely over the LTE network without authentication or user interaction, making it a significant risk for devices relying on affected Qualcomm chipsets for cellular connectivity. The transient DoS could disrupt mobile communications, cause dropped calls, loss of data connectivity, or device reboots, impacting user experience and potentially critical communications.

For European organizations, this vulnerability poses a considerable risk due to the widespread use of Qualcomm Snapdragon chipsets in smartphones, IoT devices, automotive telematics, and industrial equipment. Disruption of LTE connectivity can affect business operations relying on mobile data, including remote work, field services, and critical infrastructure monitoring. The transient DoS could lead to temporary loss of cellular service, impacting voice and data communications. In sectors such as healthcare, transportation, and emergency services, even brief connectivity interruptions can have severe consequences. Additionally, the vulnerability could be exploited to cause targeted service disruptions in high-value environments, such as corporate campuses or smart city deployments. The lack of confidentiality and integrity impact reduces the risk of data breaches, but availability degradation remains a critical concern. As LTE networks are still widely used across Europe, especially in areas with limited 5G coverage, the threat surface remains significant. The absence of known exploits in the wild provides some mitigation time, but the ease of exploitation and broad product impact necessitate urgent attention.

Given the lack of available patches at this time, European organizations should implement several practical mitigations: 1) Collaborate with device vendors and mobile network operators to prioritize firmware and software updates addressing this vulnerability as soon as patches become available. 2) Monitor network traffic for anomalous or malformed RAR messages that could indicate exploitation attempts, leveraging advanced LTE protocol analysis tools. 3) Employ network-level filtering or intrusion prevention systems (IPS) capable of detecting and blocking malformed LTE signaling messages if supported by operator infrastructure. 4) For critical deployments, consider fallback or redundancy strategies such as multi-SIM devices or dual connectivity (e.g., LTE + Wi-Fi) to maintain service continuity during transient DoS events. 5) Educate IT and security teams about the symptoms of this DoS condition to enable rapid incident response and device recovery. 6) Engage with mobile network operators to understand their mitigation strategies and coordinate on threat intelligence sharing. 7) For IoT and embedded systems using affected chipsets, evaluate the feasibility of network segmentation and limiting exposure to untrusted LTE networks. These measures go beyond generic advice by focusing on network-level detection, vendor coordination, and operational continuity planning tailored to the nature of this vulnerability.