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The vulnerability CVE-2025-20753 in MediaTek modem firmware stems from inadequate exception handling within the base station connection protocol. When User Equipment (UE) attempts to attach to a malicious rogue base station controlled by an attacker, the base station can transmit specially crafted signaling messages during the initial network entry or handshake procedures. These malicious messages, such as invalid information elements or malformed protocol data units, trigger an unexpected exception in the modem’s software stack. The firmware lacks proper try-catch or error recovery mechanisms for this specific execution path, leading to an uncaught exception. This exception causes a critical system crash or firmware panic, resulting in a complete denial of service. The modem becomes unresponsive, requiring a device reboot to restore functionality. The attack is remote and requires no user interaction, as the UE automatically scans for and connects to available base stations. No additional execution privileges are needed, making exploitation straightforward for an attacker with a software-defined radio setup. The flaw resides in the baseband processing unit where incoming radio resource control messages are parsed. The patch, identified by MOLY01689252, addresses this by implementing comprehensive input validation and adding robust exception handlers around the vulnerable code sections to prevent the crash.
Platform: MediaTek Modem
Version: Not Specified
Vulnerability: Remote Denial Service
Severity: Critical
Date: 01 Dec 2025
Prediction: Patched Dec 2025
What Undercode Say:
Analytics
bash
dmesg | grep modem
logcat | grep modem
strings /dev/modem0 | grep -i error
How Exploit:
Setup rogue base station.
Broadcast malicious beacon signals.
Force UE connection.
Protection from this CVE
Apply MediaTek patch.
Update modem firmware.
Use network security settings.
Impact:
Modem system crash.
Remote service disruption.
Device reboot required.
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Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
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