CVE-2000-0459 is a medium-severity vulnerability affecting multiple versions of the IMP (Internet Messaging Program) software, specifically versions 2.0.9 through 2.2_pre12. The vulnerability arises because IMP does not properly clean up temporary files when the MSWordView application quits prematurely. MSWordView is an application used to view Microsoft Word documents, and IMP integrates with it to handle document requests. When a local user requests a large number of documents and then prematurely stops the request—causing MSWordView to quit unexpectedly—IMP fails to remove the temporary files it created during this process. This results in the accumulation of leftover files on the disk, which can eventually fill up the disk space. The consequence is a denial of service (DoS) condition, where legitimate users or processes may be unable to write new data or operate normally due to lack of available disk space. The vulnerability does not impact confidentiality or integrity, as it does not allow unauthorized data access or modification. It requires no authentication and can be triggered by local users, meaning an attacker must have local access to the system. The CVSS score of 5.0 reflects a medium severity, with network attack vector, low attack complexity, no authentication required, and impact limited to availability. No patches are available for this vulnerability, and there are no known exploits in the wild. The vulnerability is dated from 2000, indicating it affects legacy systems that may still be in use in some environments. Given the age and nature of the software, modern systems are unlikely to be affected unless legacy IMP installations remain active.

For European organizations, the primary impact of CVE-2000-0459 is a denial of service caused by disk space exhaustion on systems running vulnerable versions of IMP integrated with MSWordView. This could disrupt email or document handling services relying on IMP, potentially affecting business continuity. Organizations with legacy infrastructure or specialized environments that still use IMP may experience operational interruptions. The impact is localized to availability and does not compromise sensitive data confidentiality or integrity. However, disk space exhaustion can cascade into broader system instability or service outages if critical systems are affected. The risk is higher in organizations with limited monitoring of disk usage or those that allow local user access to mail or document servers. Given the lack of patches, mitigation relies on operational controls rather than software fixes. The threat is less relevant to organizations that have migrated to modern messaging platforms or document viewers. Nonetheless, awareness is important for legacy system administrators to prevent inadvertent denial of service conditions.

Since no patches are available for this vulnerability, European organizations should focus on operational and configuration mitigations. First, restrict local user access to systems running IMP to trusted personnel only, minimizing the risk of intentional or accidental exploitation. Second, implement strict disk space monitoring and alerting to detect unusual accumulation of temporary files early, enabling prompt cleanup before disk exhaustion occurs. Third, configure IMP or the underlying system to periodically clean up temporary files, possibly through scheduled scripts or system maintenance tasks. Fourth, consider replacing or upgrading IMP and MSWordView with modern, supported software that does not exhibit this vulnerability. Fifth, educate users about the risks of prematurely terminating document requests and encourage proper usage patterns. Finally, isolate legacy systems from critical network segments to limit the impact of any denial of service conditions. These practical steps help mitigate the risk in the absence of official patches.