CVE-2025-27918 is a security vulnerability identified in AnyDesk versions before 9.0.0. The flaw arises from an integer overflow that triggers a heap-based buffer overflow during the handling of UDP packets. Specifically, the vulnerability manifests when processing the Identity user image within the Discovery feature or during connection establishment between AnyDesk clients. An integer overflow occurs when a calculation exceeds the maximum value an integer type can hold, causing it to wrap around and potentially lead to memory corruption. This memory corruption, in the form of a heap-based buffer overflow, can be exploited by an attacker to overwrite memory, potentially allowing arbitrary code execution or causing application crashes (denial of service). The attack vector is remote and does not require prior authentication, as it exploits UDP packets sent between clients. Although no known public exploits are reported yet, the vulnerability is critical due to the nature of the flaw and the widespread use of AnyDesk for remote desktop access. The lack of a CVSS score indicates the need for a severity assessment based on the technical details. The vulnerability was reserved in March 2025 and published in November 2025, indicating recent discovery and disclosure. No patches or mitigations are currently linked, emphasizing the importance of vendor updates and network-level protections.

For European organizations, the impact of CVE-2025-27918 could be significant. AnyDesk is widely used for remote desktop access in corporate, governmental, and critical infrastructure environments across Europe. Successful exploitation could allow attackers to execute arbitrary code remotely, leading to full system compromise, data breaches, or disruption of business operations. The vulnerability could also facilitate lateral movement within networks if attackers gain initial footholds via compromised endpoints. Confidentiality, integrity, and availability of affected systems are all at risk. Given the remote and unauthenticated nature of the exploit, attackers could target exposed AnyDesk clients or servers over UDP, increasing the attack surface. This is particularly concerning for sectors relying heavily on remote work and secure remote access, such as finance, healthcare, and government agencies in Europe. The absence of known exploits provides a window for proactive defense, but also means organizations must act quickly once patches are available.

To mitigate CVE-2025-27918, European organizations should prioritize upgrading AnyDesk to version 9.0.0 or later as soon as the vendor releases a patch addressing this vulnerability. Until then, organizations should implement network-level controls to restrict UDP traffic associated with AnyDesk, especially from untrusted networks. Deploying intrusion detection/prevention systems (IDS/IPS) with signatures or heuristics to detect anomalous UDP packets related to AnyDesk Discovery or connection establishment can help identify exploitation attempts. Network segmentation should be enforced to limit exposure of critical systems running AnyDesk. Additionally, organizations should audit and monitor AnyDesk usage logs for unusual connection patterns or crashes that may indicate exploitation attempts. Employee awareness training about the risks of remote desktop software vulnerabilities and enforcing multi-factor authentication (MFA) for remote access sessions can further reduce risk. Finally, maintain up-to-date backups and incident response plans to quickly recover from potential compromises.