CVE-2020-37164 in AbsoluteTelnet
Summary
by MITRE • 02/07/2026
AbsoluteTelnet 11.12 contains a denial of service vulnerability that allows local attackers to crash the application by supplying an oversized license name. Attackers can generate a 2500-character payload and paste it into the license entry field to trigger an application crash.
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Analysis
by VulDB Data Team • 02/19/2026
The vulnerability identified as CVE-2020-37164 affects AbsoluteTelnet version 11.12, a network communication software that provides telnet and ssh client functionality. This issue represents a classic buffer overflow condition that occurs when the application fails to properly validate input length during license registration processes. The flaw exists within the software's license validation mechanism where it accepts user-supplied license names without implementing adequate length restrictions or input sanitization measures. Attackers exploiting this vulnerability can craft a malicious payload consisting of 2500 characters and submit it through the standard license entry interface, causing the application to crash and terminate unexpectedly. This type of vulnerability demonstrates poor input validation practices and inadequate memory management within the application's core components.
The technical implementation of this vulnerability stems from the application's failure to enforce proper bounds checking on license name fields during the registration process. When the software receives an oversized input string, it attempts to process the data without verifying that the input length conforms to acceptable parameters. This creates a condition where the application's internal buffers cannot accommodate the excessive data, leading to memory corruption and subsequent application termination. The vulnerability operates at the application layer and requires local access to exploit, as attackers must have the ability to interact with the software's user interface to submit the malicious payload. According to the CWE database, this corresponds to CWE-122, which describes heap-based buffer overflow conditions that occur when insufficient space is allocated for data processing. The flaw also aligns with ATT&CK technique T1499.004, which covers network denial of service attacks through resource exhaustion or application corruption.
The operational impact of this vulnerability extends beyond simple application instability, as it can potentially disrupt legitimate network operations that depend on AbsoluteTelnet for remote access and management tasks. Local attackers with access to the system can leverage this weakness to repeatedly crash the application, creating persistent service interruptions that may affect network administrators' ability to perform essential remote maintenance activities. The vulnerability is particularly concerning in enterprise environments where telnet clients are used for critical infrastructure management, as repeated exploitation could lead to extended downtime and operational disruption. Additionally, the crash condition may be exploited as part of a broader attack strategy to disable security monitoring tools or management applications that rely on telnet connectivity. The relatively simple nature of the exploit, requiring only a 2500-character string, makes this vulnerability particularly dangerous as it can be easily automated and deployed without significant technical expertise. Organizations using AbsoluteTelnet 11.12 should immediately implement mitigation strategies including input validation enforcement, application hardening measures, and monitoring for unusual crash patterns that may indicate exploitation attempts.