CVE-2025-5342 identifies a Regular Expression Denial of Service (ReDOS) vulnerability classified under CWE-400 (Uncontrolled Resource Consumption) in the search module of Zohocorp's ManageEngine Exchange Reporter Plus product, affecting versions up to 5721. The vulnerability arises from inefficient or poorly designed regular expressions used in the search functionality, which can be exploited by an attacker to craft malicious input that causes excessive CPU consumption, leading to service degradation or denial of service. The attack vector is network-based, requiring only low privileges and no user interaction, making it relatively accessible to internal or external threat actors with some access to the system. The CVSS 3.1 score of 4.3 reflects a medium severity, primarily due to the impact on availability without compromising confidentiality or integrity. No known exploits have been reported in the wild, and no official patches have been released at the time of publication. The vulnerability's exploitation could disrupt the availability of Exchange reporting services, impacting monitoring and operational visibility. Given the critical role of Exchange Reporter Plus in enterprise environments for Microsoft Exchange server reporting, this vulnerability could affect incident response and system administration workflows. The lack of patches necessitates proactive mitigation and monitoring strategies.

For European organizations, the primary impact of CVE-2025-5342 is the potential denial of service on ManageEngine Exchange Reporter Plus, which could disrupt Exchange server reporting and monitoring capabilities. This disruption may delay detection of email system issues, compliance reporting, and operational decision-making. Organizations relying heavily on this tool for Exchange infrastructure visibility may experience reduced situational awareness, increasing the risk of undetected email system failures or security incidents. While the vulnerability does not directly compromise data confidentiality or integrity, the availability impact could affect business continuity and incident response effectiveness. The medium CVSS score suggests moderate risk, but the ease of exploitation and network accessibility elevate concern, especially in environments with limited network segmentation or weak access controls. The absence of known exploits reduces immediate risk but does not eliminate the threat, as attackers may develop exploits once the vulnerability details are widely known.

1. Monitor resource utilization of ManageEngine Exchange Reporter Plus servers closely to detect abnormal CPU spikes or service slowdowns indicative of ReDOS exploitation attempts. 2. Restrict network access to the Exchange Reporter Plus search module to trusted internal IP addresses and limit exposure to external networks. 3. Implement strict access controls and least privilege principles for user accounts interacting with the vulnerable module to reduce attack surface. 4. Employ Web Application Firewalls (WAFs) or Intrusion Prevention Systems (IPS) capable of detecting and blocking suspicious regular expression patterns or excessive request rates targeting the search functionality. 5. Engage with Zohocorp support channels to obtain updates on patch availability and apply security updates promptly once released. 6. Consider temporary disabling or limiting the search module functionality if feasible until a patch is available. 7. Conduct internal security awareness to inform administrators about this vulnerability and encourage vigilance for unusual system behavior. 8. Review and harden network segmentation around critical Exchange infrastructure to contain potential exploitation impact.