Researchers have uncovered a new flaw in Unisoc T612 modem firmware that, when chained with a previously disclosed remote code execution (RCE) vulnerability, could allow an attacker to gain privileged access to the Android kernel on affected devices.
A threat actor could trigger the attack by first delivering a malicious payload to the phone's modem via the previous RCE vulnerability and then placing a video call to the device, which the victim would need to answer for the exploit to work.
A Two-Stage Unisoc Attack Chain
Researchers at SSD Secure Disclosure, who discovered both the new flaw in Unisoc's T612 modem firmware and the previously disclosed RCE vulnerability, demonstrated the attack chain in a controlled setting against a Realme C33 smartphone running the affected firmware.
SSD confirmed the vulnerability on a Xiaomi Redmi A5 running the January 2026 Android security patch and a Motorola E13 running the February 2025 patch. The company did not indicate if it believed devices from other manufacturers were affected as well.
"We have tried to reach out to the vendor through multiple channels (email and LinkedIn) but have not been able to receive any response," SSD Secure wrote in the research post.
Unisoc Technologies Co. Ltd. is a Chinese semiconductor design company that develops chipsets and platforms for mobile phones, IoT (Internet of Things) devices, automotive systems, tablets, wearables and other connected devices. Multiple mobile device manufacturers including Motorola, Samsung, Realme, Nokia, and ZTE currently use Unisoc chipsets.