CVE-2019-13451 in Xymon
Summary
by MITRE
In Xymon through 4.3.28, a buffer overflow vulnerability exists in history.c.
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Analysis
by VulDB Data Team • 08/27/2025
The vulnerability identified as CVE-2019-13451 represents a critical buffer overflow condition within the Xymon monitoring system version 4.3.28 and earlier. This flaw resides in the history.c source file, which is responsible for managing historical data processing within the Xymon framework. Xymon is a widely deployed network monitoring and alerting system that collects, processes, and displays system performance metrics across distributed environments. The buffer overflow vulnerability emerges when the application processes certain input data related to historical monitoring records, creating an exploitable condition that could allow attackers to manipulate memory structures and potentially execute arbitrary code.
The technical implementation of this vulnerability stems from inadequate bounds checking within the history.c module where string operations occur without proper validation of input lengths. When Xymon processes historical data entries, particularly those containing malformed or excessively long data sequences, the application fails to validate the buffer boundaries before copying data into fixed-length memory structures. This classic buffer overflow scenario allows an attacker to overwrite adjacent memory locations, potentially corrupting program execution flow or injecting malicious code. The vulnerability operates at the application layer and requires successful exploitation through controlled input manipulation, typically involving crafted historical data records that exceed expected buffer capacities.
The operational impact of this vulnerability extends beyond simple system instability, as it provides attackers with potential paths to achieve remote code execution within the context of the Xymon service. Since Xymon typically runs with elevated privileges to monitor system resources effectively, successful exploitation could result in complete system compromise. The vulnerability affects organizations relying on Xymon for critical infrastructure monitoring, where attackers could manipulate historical data feeds to trigger the overflow condition. This presents particular risk in environments where Xymon receives data from multiple sources or where historical data processing is automated, as the attack surface expands to include any data ingestion points that feed into the vulnerable history.c module.
Mitigation strategies for CVE-2019-13451 should prioritize immediate patching of affected Xymon installations to version 4.3.29 or later, which contains the necessary buffer overflow protections. Organizations should implement input validation controls at all data entry points to prevent malformed historical records from reaching the vulnerable code path. Network segmentation and access controls should limit data sources that can submit information to the Xymon system, reducing potential attack vectors. Additionally, monitoring for unusual data patterns or attempts to submit oversized records could help detect exploitation attempts. This vulnerability aligns with CWE-121, which describes buffer overflow conditions in stack-based buffers, and may map to ATT&CK technique T1059.007 for remote code execution through application vulnerabilities, emphasizing the need for comprehensive defensive measures including regular security updates, input sanitization, and runtime monitoring of system processes.