CVE-2026-20596 in Modem
Summary
by MITRE • 11/02/2026
In Modem, there is a possible out of bounds read 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: MOLY01758225; Issue ID: MSV-8910.
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Analysis
by VulDB Data Team • 11/02/2026
The vulnerability described involves an out-of-bounds read condition within a mobile modem component, specifically triggered by improper input validation during the processing of data from connected network entities. This flaw allows for remote exploitation without requiring any prior execution privileges on the target device or user interaction, making it particularly dangerous in scenarios where a User Equipment connects to a rogue base station controlled by an adversary. The core technical issue stems from insufficient boundary checks when handling inputs received over the air interface, which can lead the modem firmware to access memory locations outside of its allocated buffer space. Such improper input validation is a classic example of CWE-125, Out-of-bounds Read, where the software reads data beyond the intended boundaries of a buffer, potentially exposing sensitive information or causing unpredictable behavior depending on what resides in that adjacent memory.
From an operational perspective, this vulnerability primarily facilitates remote denial of service attacks against mobile devices and network infrastructure. When a UE connects to a malicious base station, the attacker can craft specific malformed messages that exploit the input validation gap within the modem stack. The resulting out-of-bounds read may cause the modem firmware to crash or enter an unstable state, effectively rendering the device unable to maintain connectivity with legitimate networks. This disruption impacts not only individual users but also broader network availability if multiple devices are affected simultaneously. Since no user interaction is required for exploitation, attackers can execute these attacks passively by simply broadcasting rogue base station signals within range of vulnerable modems, leveraging tools such as software-defined radios to simulate malicious cellular infrastructure and deliver the exploit payload automatically upon connection attempts.
The attack vector aligns with techniques observed in advanced persistent threat campaigns targeting mobile networks, particularly those involving IMSI catchers or fake cell towers designed to intercept communications or disrupt service. In terms of cybersecurity frameworks, this scenario reflects aspects of MITRE ATT&CK technique T1498, Network Denial of Service, specifically focusing on infrastructure denial via exploitation of communication protocols. Additionally, the lack of proper input validation highlights weaknesses in secure coding practices related to memory safety and boundary checking, which are critical for maintaining integrity in embedded systems like modems that operate with limited resources and strict real-time constraints.
To mitigate this vulnerability, manufacturers must implement rigorous input validation mechanisms within the modem firmware to ensure all incoming data from base stations is thoroughly checked against expected formats and lengths before processing. Patch ID MOLY01758225 addresses these issues by enhancing boundary checks and improving error handling routines to prevent out-of-bounds accesses. Organizations relying on affected devices should apply this patch promptly through over-the-air updates or manual firmware installations where applicable. Furthermore, deploying network monitoring solutions capable of detecting anomalies in cellular signaling traffic can help identify rogue base stations early, reducing the window of opportunity for attackers to exploit such vulnerabilities. Regular security audits and adherence to secure development lifecycle principles will further strengthen resilience against similar threats targeting mobile communication protocols.