Smartphones at Risk: How a Single Packet Could Crash Your Connection

In today’s ever-connected world, smartphones are indispensable, keeping us linked through calls, texts, and data services. At the heart of this connectivity lies the communication modem—also known as the baseband chip—integral to maintaining a smartphone’s link to mobile networks. However, recent findings by researchers from the Korea Advanced Institute of Science and Technology (KAIST) signal a critical vulnerability that poses a significant risk to these ubiquitous devices.

Researchers using an innovative testing framework, LLFuzz (Lower Layer Fuzz), have unveiled a concerning security flaw in the lower layers of smartphone communication modems. The study indicates that with a single manipulated wireless packet, these vulnerabilities could incapacitate mobile connectivity or potentially allow remote code execution on a device. Testing encompassed 15 commercial smartphones from major brands such as Apple, Samsung, Google, and Xiaomi, which revealed 11 vulnerabilities, seven of which have been credited with official CVE numbers.

The core issue resides in the lower layers of mobile communication—specifically the RLC, MAC, PDCP, and PHY layers—where encryption and authentication are typically absent. This absence creates a structural weak point, exposing smartphones to potential exploitation by malicious external signals. Researchers demonstrated their findings with a software-defined radio device that injected malformed packets into smartphones, effectively crashing the baseband and halting connectivity.

The vulnerabilities affect a broad range of devices, including premium and budget smartphones, tablets, smartwatches, and IoT devices, using chipsets from key manufacturers like Qualcomm, MediaTek, Samsung, and Apple. For instance, vulnerabilities like CVE-2025-21477 and CVE-2024-27870 impact dozens of Qualcomm and Apple chipsets respectively, illustrating the widespread risk across the device ecosystem.

Professor Yongdae Kim from KAIST emphasizes the urgent need for industry-standardized security testing. With further analysis and tool development underway, the research team aims to address vulnerabilities across newer 5G networks as well.

Key Takeaways:

1. Critical Security Flaw: A single, manipulated wireless packet can disrupt a smartphone’s communication capabilities and potentially allow remote code execution.

2. Widespread Impact: Vulnerabilities affect major brands, including Apple, Samsung, and Google, impacting a variety of devices from smartphones to IoT gadgets.

3. Need for Standardization: The findings underscore the necessity of standardized security testing for mobile communication modems, especially in lower layers lacking encryption or authentication.

4. Call to Action: There is a pressing need for ongoing research and industry-wide collaborations to safeguard against these vulnerabilities, ensuring the security of global mobile networks.

These discoveries highlight the critical importance of securing the foundational technologies that drive our digital lives. As devices grow ever more interconnected, proactive security measures become paramount to maintain the integrity and reliability of our communication networks.