CVE-2026-20457 in MT2735
Summary
by MITRE • 07/01/2026
In Modem, there is a possible system crash due to improper input validation. This could lead to remote denial of service, if a UE has connected to a rogue base station controlled by the attacker, with no additional execution privileges needed. User interaction is not needed for exploitation. Patch ID: MOLY01826924; Issue ID: MSV-7301.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 07/01/2026
This vulnerability represents a critical remote denial of service flaw within modem firmware that stems from inadequate input validation mechanisms. The issue manifests when a user equipment device connects to a malicious base station controlled by an attacker, creating a scenario where the modem's processing logic fails to properly validate incoming data streams. The vulnerability operates at the network protocol level where malformed or unexpected inputs can cause the modem's core processing units to enter an unstable state resulting in system crash and complete service disruption. This represents a significant security concern as it allows attackers to remotely compromise device functionality without requiring any elevated privileges or user interaction, making it particularly dangerous in mobile network environments where devices continuously connect to various base stations. The vulnerability is classified under CWE-20, which specifically addresses improper input validation issues, and aligns with ATT&CK technique T1499.1 for endpoint denial of service attacks.
The technical implementation of this flaw occurs during the modem's normal operation when handling network protocol communications from rogue base stations. When a legitimate device connects to an attacker-controlled base station, the malicious infrastructure can craft specific network packets or communication sequences that exploit the input validation gaps in the modem firmware. These crafted inputs cause the modem's processing logic to encounter unexpected data patterns that trigger memory corruption or execution flow disruptions within the device's operating system components. The vulnerability is particularly concerning because it operates at a low level within the modem's core functionality, making it difficult to detect through traditional network monitoring approaches and allowing for complete system instability that results in device unresponsiveness.
The operational impact of this vulnerability extends beyond simple service disruption as it can effectively render mobile devices unusable for communication purposes. When exploited successfully, the remote denial of service attack causes complete modem failure requiring manual intervention or device reboot to restore functionality. This creates significant risk for users who may be unable to access critical communications services during an attack, particularly in emergency situations where mobile connectivity is essential. The vulnerability affects all devices running the affected modem firmware versions and presents a particular challenge for network operators who must maintain service availability across their entire device fleet. The lack of requirement for additional execution privileges or user interaction makes this vulnerability extremely dangerous as attackers can target large numbers of devices simultaneously without detection, creating potential for widespread service disruption across mobile networks.
Mitigation strategies for this vulnerability should focus on immediate firmware updates provided by device manufacturers and network operators to address the specific input validation gaps in the modem firmware. The patch MOLY01826924 specifically targets the identified validation issues and should be deployed as a priority across all affected devices. Network operators should also implement monitoring systems to detect potential rogue base station activities and establish protocols for rapid response to suspected attacks. Additional defensive measures include implementing network-level filtering mechanisms that can identify and block suspicious communication patterns originating from known malicious base stations, as well as establishing secure communication protocols between legitimate base stations and user equipment to prevent unauthorized access to modem functions. Organizations should also consider maintaining backup communication methods and emergency procedures to ensure service continuity during potential exploitation events, while conducting regular vulnerability assessments to identify similar input validation issues in other network components.
The vulnerability demonstrates how fundamental firmware-level security flaws can create significant risk for mobile network infrastructure and highlights the importance of robust input validation across all system components. It underscores the necessity for comprehensive security testing of network protocol implementations and emphasizes that even seemingly minor validation gaps can result in critical service disruptions. Organizations must recognize that modem-level vulnerabilities represent a unique challenge in mobile security environments where device manufacturers and network operators must coordinate closely to ensure timely patch deployment and effective threat mitigation strategies.