CVE-2026-21550 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 that stems from inadequate input validation mechanisms within the device's communication protocols. The flaw allows attackers to craft malicious inputs that can trigger unexpected behavior in the modem's processing functions, potentially leading to complete system disruption without requiring any elevated privileges or specialized execution capabilities. Such vulnerabilities typically arise when modem manufacturers fail to implement comprehensive sanitization checks on data received through various communication channels including serial interfaces, network protocols, or command-line inputs. The absence of proper validation creates opportunities for attackers to exploit buffer overflows, format string vulnerabilities, or other input-related weaknesses that can cause the modem to crash or become unresponsive.
The remote nature of this denial of service vulnerability means that adversaries can initiate attacks from external networks without needing physical access to the device or local network privileges. This characteristic significantly increases the attack surface and potential impact scope, as the vulnerability can be exploited from anywhere on the internet. The lack of additional execution privileges required for exploitation suggests that the vulnerability exists at a level where basic input handling fails to properly validate data integrity, potentially affecting protocols such as ppp, tcp/ip, or other communication standards that modems utilize. From an operational perspective, this vulnerability represents a serious threat to network reliability and availability since it can cause complete disruption of modem services without requiring complex attack vectors.
The technical implementation of this flaw likely occurs in the modem's protocol parsing or command processing components where incoming data streams are not adequately validated before being processed by core system functions. This type of vulnerability typically falls under common weakness enumerations such as cwe-20, which describes improper input validation, and may also relate to cwe-129, indicating issues with input validation that allow for buffer overflows or other memory corruption scenarios. The operational impact extends beyond simple service disruption to potentially affecting broader network infrastructure depending on the role the modem plays within the communication ecosystem. Organizations relying on modem-based connectivity for critical services may face significant downtime and potential data loss if this vulnerability is exploited.
Security mitigations should focus on implementing robust input validation mechanisms throughout all modem communication interfaces, including regular firmware updates from manufacturers that address known vulnerabilities. Network segmentation strategies can help limit the impact of successful exploitation by isolating modem devices from critical network segments. Monitoring systems should be deployed to detect unusual traffic patterns or service disruptions that may indicate exploitation attempts. Additionally, organizations should implement proper access controls and authentication mechanisms to prevent unauthorized modification of modem configurations. The vulnerability aligns with attack techniques documented in the attack pattern taxonomy under methods such as command injection or protocol manipulation where adversaries leverage input validation weaknesses to gain control over device operations. Regular security assessments and penetration testing of network infrastructure can help identify similar vulnerabilities before they can be exploited by malicious actors.