CVE-2002-0092 in CVS
Summary
by MITRE
CVS before 1.10.8 does not properly initialize a global variable, which allows remote attackers to cause a denial of service (server crash) via the diff capability.
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Analysis
by VulDB Data Team • 09/23/2025
The vulnerability identified as CVE-2002-0092 affects the Concurrent Versions System (CVS) version control software prior to 1.10.8, representing a critical flaw in the software's initialization process that can be exploited remotely to cause service disruption. This issue stems from improper handling of a global variable within the diff functionality of the CVS server component, creating a condition that can be triggered by malicious input to crash the server process and render the version control service unavailable to legitimate users.
The technical root cause of this vulnerability lies in the insufficient initialization of a global variable within the diff command implementation. When remote users submit crafted requests through the diff capability, the uninitialized variable contains unpredictable data from previous operations or memory contents, leading to erratic behavior in the server's execution flow. This uninitialized variable manipulation creates a path for attackers to force the CVS server into an invalid state where memory access violations or arithmetic errors occur, ultimately resulting in a crash that terminates the server process and prevents further operations.
From an operational perspective, this vulnerability presents a significant risk to development environments that rely on CVS for source code management, as attackers can exploit this weakness to perform denial of service attacks against version control servers. The impact extends beyond simple service interruption since many development workflows depend on continuous access to source code repositories, making such attacks particularly damaging to development teams and organizations that depend on stable version control infrastructure. The remote nature of the exploit means that attackers do not need physical access to the system or local network privileges to carry out the attack, making it particularly dangerous in networked environments.
The vulnerability aligns with CWE-457 which describes "Use of Uninitialized Variable" and demonstrates how improper initialization can lead to system instability and denial of service conditions. From an attack framework perspective, this weakness maps to ATT&CK technique T1499.004 for "Endpoint Denial of Service" and represents a classic example of how seemingly minor initialization flaws can be amplified into significant security incidents. The vulnerability also reflects broader patterns of memory safety issues that have historically plagued software systems, particularly in legacy codebases where modern security practices were not fully implemented.
Organizations should immediately upgrade their CVS installations to version 1.10.8 or later to remediate this vulnerability, as no effective workarounds exist for the uninitialized variable issue. System administrators should also implement network-level controls to restrict access to CVS servers and monitor for unusual diff command usage patterns that might indicate exploitation attempts. The fix addresses the core initialization problem by ensuring proper variable setup before the diff functionality executes, preventing the unpredictable behavior that led to server crashes and maintaining the stability of version control operations. Regular security assessments of version control systems should include checks for similar initialization vulnerabilities that could affect other legacy software components.