CVE-2026-20479 in MT2735
Summary
by MITRE • 08/03/2026
In Modem, there is a possible out of bounds read due to a missing bounds check. 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: MOLY00741071; Issue ID: MSV-7620.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 08/03/2026
This vulnerability represents a critical out-of-bounds read condition within modem firmware that arises from insufficient input validation mechanisms. The flaw occurs when a user equipment device connects to a malicious base station controlled by an attacker, creating a scenario where the modem processes malformed data without proper boundary checking. The absence of bounds verification allows the modem to attempt reading memory locations beyond the allocated buffer boundaries, potentially causing system instability or complete service disruption.
The vulnerability's remote exploitation capability stems from the fact that no user interaction is required for successful exploitation, making it particularly dangerous in mobile network environments where devices frequently connect to various base stations. Attackers can leverage this weakness by establishing rogue base station infrastructure that deliberately sends malformed signaling messages or data packets designed to trigger the out-of-bounds read condition. The lack of additional execution privileges needed further reduces the attack vector complexity, as the attacker only requires network access rather than physical device compromise or administrative credentials.
From a technical operational perspective, this vulnerability directly impacts mobile network reliability and service availability, potentially enabling denial of service attacks that can affect individual devices or broader network segments. The issue manifests when the modem firmware fails to validate incoming data lengths against expected buffer sizes during processing of communication protocols, leading to memory access violations that typically result in system crashes or reboot cycles. This scenario creates a persistent threat vector where attackers can repeatedly disrupt service without requiring device-specific access or complex exploitation techniques.
The security implications extend beyond simple denial of service to encompass potential information disclosure risks and system stability concerns within mobile network infrastructure. According to CWE classification, this represents a variant of CWE-129 Input Validation and Bounds Checking, specifically addressing insufficient validation of input data boundaries. The vulnerability aligns with ATT&CK technique T1566.001 Validating Credentials and T1498.001 Network Denial of Service, demonstrating how modem-level flaws can enable sophisticated attack campaigns targeting mobile communication networks.
Mitigation strategies should focus on immediate firmware updates addressing the specific patch MOLY00741071 which resolves the bounds checking deficiency in the modem's data processing routines. Network operators must implement robust base station monitoring systems to detect and isolate rogue infrastructure, while device manufacturers should consider implementing additional runtime protections such as memory sanitization checks and enhanced input validation layers. The vulnerability highlights the critical importance of secure firmware development practices and emphasizes the need for comprehensive security testing of network infrastructure components that operate in untrusted environments where malicious actors may attempt to manipulate communication flows through compromised base stations or other network elements.