CVE-2026-21552 in T8100
Summary
by MITRE • 08/03/2026
In modem, there is a possible improper input validation. This could lead to remote denial of service with no additional execution privileges needed
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Analysis
by VulDB Data Team • 08/03/2026
This vulnerability represents a critical weakness in modem firmware architecture that stems from inadequate input validation mechanisms within the device's communication protocols. The flaw exists at the boundary between incoming data streams and internal processing functions, where malformed or unexpected inputs are not properly sanitized before being processed by the modem's core operational components. Such deficiencies create exploitable pathways that malicious actors can leverage to disrupt normal service operations without requiring elevated privileges or specialized execution capabilities. The vulnerability manifests when the modem receives malformed packets, unexpected command sequences, or corrupted data streams through its various communication interfaces including serial ports, network connections, or wireless protocols. These improperly validated inputs can trigger buffer overflows, memory corruption issues, or state machine disruptions that ultimately result in complete service termination or system instability.
The technical implementation of this vulnerability aligns with common CWE classifications related to input validation failures and improper error handling within embedded systems. From an operational perspective, this weakness directly maps to ATT&CK technique T1499.004 which encompasses network denial of service attacks targeting communication infrastructure. The attack vector requires minimal prerequisites since the vulnerability does not necessitate code execution privileges or administrative access, making it particularly dangerous in environments where modems serve as critical communication endpoints for network infrastructure, industrial control systems, or IoT deployments. Attackers can exploit this flaw by sending carefully crafted malformed data to the modem's input interfaces, causing the device to enter an unrecoverable state or crash entirely.
The operational impact of this vulnerability extends beyond simple service disruption to encompass broader implications for network reliability and business continuity. When modems become unavailable due to denial of service conditions, they can compromise entire communication chains including internet connectivity, voice services, or critical infrastructure monitoring systems. The vulnerability affects all versions of the modem firmware that lack proper input validation routines, particularly impacting devices deployed in telecommunications networks, enterprise environments, or industrial settings where continuous communication availability is paramount. Organizations must consider the cascading effects of such failures, as modem outages can propagate through network architectures and affect multiple dependent systems simultaneously.
Mitigation strategies should focus on implementing comprehensive input validation mechanisms across all modem interfaces including firmware updates that enforce strict data format checking, buffer size limitations, and proper error handling routines. Network segmentation and monitoring solutions can help detect anomalous traffic patterns that might indicate exploitation attempts. Regular vulnerability assessments and penetration testing of modem deployments are essential to identify similar weaknesses in other network components. Security patches should be deployed immediately upon availability, with particular attention to embedded systems where firmware updates may require specialized procedures or hardware intervention. The implementation of intrusion detection systems specifically configured to monitor modem communication patterns can provide early warning capabilities for potential exploitation attempts. Organizations should also establish incident response protocols that include rapid recovery procedures for modem failures and maintain backup communication pathways to ensure continued operational capability during remediation activities.