CVE-2000-0338 in CVS
Summary
by MITRE
Concurrent Versions Software (CVS) uses predictable temporary file names for locking, which allows local users to cause a denial of service by creating the lock directory before it is created for use by a legitimate CVS user.
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Analysis
by VulDB Data Team • 04/21/2026
The vulnerability identified as CVE-2000-0338 resides within Concurrent Versions Software CVS, a widely used version control system that has been integral to software development workflows since its inception. This flaw represents a critical security oversight that directly impacts the integrity and availability of CVS operations within development environments. The vulnerability specifically targets the temporary file naming mechanism employed by CVS during its locking procedures, creating a predictable pattern that malicious users can exploit to disrupt normal system operations.
The technical flaw stems from CVS's implementation of temporary file handling during concurrent access scenarios. When multiple users attempt to access the same repository simultaneously, CVS creates lock files to prevent conflicts and maintain data consistency. However, the system generates these lock file names using predictable algorithms that do not incorporate sufficient randomness or entropy. This predictability allows local attackers to pre-create lock directories or files with the same names that CVS would subsequently generate, effectively interfering with legitimate operations.
The operational impact of this vulnerability extends beyond simple denial of service conditions to potentially compromise the entire version control workflow. Local users with access to the system can exploit this weakness to prevent legitimate CVS operations from completing successfully, leading to cascading failures in development processes. When an attacker creates a lock file before CVS can do so, the legitimate user's operation fails, causing the system to hang or terminate unexpectedly. This disruption can halt critical development activities, especially in environments where multiple developers collaborate on shared codebases.
From a cybersecurity perspective, this vulnerability aligns with CWE-330, which addresses the use of insecure random number generators, and represents a classic example of predictable temporary file creation that violates fundamental security principles. The issue also maps to ATT&CK technique T1499.004, which involves network disruption through denial of service attacks, though in this case the attack vector is local rather than network-based. The vulnerability demonstrates how seemingly minor implementation details in software can create significant security risks when proper entropy and randomization are not applied to critical system components.
The mitigation strategy for CVE-2000-0338 requires immediate attention through patching and system hardening measures. Organizations should upgrade to patched versions of CVS that implement proper randomization in temporary file naming procedures. Additionally, system administrators should consider implementing file system permissions that restrict unauthorized creation of temporary directories, and monitor for suspicious file creation patterns that may indicate exploitation attempts. The vulnerability serves as a reminder of the critical importance of entropy in security-sensitive operations and the necessity of robust temporary file management in multi-user environments where concurrency is a factor.