CVE-2025-27916 is a security vulnerability identified in AnyDesk remote desktop software versions up to 9.0.4. The issue arises when a connection between two AnyDesk clients is established using an IP address rather than a standard AnyDesk ID. Under these conditions, an attacker can manipulate the data transmitted during the connection setup phase to spoof the AnyDesk ID. This spoofing could allow the attacker to impersonate a legitimate client or server, potentially enabling unauthorized access to remote systems or facilitating man-in-the-middle attacks. The vulnerability compromises the integrity and confidentiality of the remote session by undermining the trust model based on AnyDesk IDs. No CVSS score has been assigned yet, and no public exploits have been reported. The lack of patches at the time of disclosure means organizations must rely on interim mitigations. The vulnerability is particularly concerning because it does not require authentication or user interaction to exploit once a connection via IP is initiated. This flaw could be leveraged to bypass access controls or intercept sensitive data during remote sessions, posing significant risks to organizations relying on AnyDesk for remote administration or support.

For European organizations, the impact of CVE-2025-27916 could be substantial. AnyDesk is widely used across Europe for remote work, IT support, and critical infrastructure management. Exploitation could lead to unauthorized access to sensitive systems, data breaches, and potential disruption of business operations. Confidentiality is at risk as attackers could intercept or alter data during remote sessions. Integrity is compromised through ID spoofing, enabling attackers to masquerade as trusted clients or servers. Availability could also be affected if attackers disrupt remote connections or use the vulnerability to launch further attacks. Sectors such as finance, healthcare, government, and critical infrastructure, which heavily depend on secure remote access, are particularly vulnerable. The lack of authentication requirements for exploitation increases the threat level, making it easier for attackers to target European organizations that use IP-based connections in AnyDesk.

Until an official patch is released, European organizations should implement several specific mitigations: 1) Avoid establishing AnyDesk connections directly via IP addresses; instead, use the standard AnyDesk ID system which is less susceptible to spoofing. 2) Restrict AnyDesk usage to trusted networks and enforce network-level segmentation to limit exposure. 3) Employ VPNs or encrypted tunnels to protect remote session data from interception or manipulation. 4) Monitor AnyDesk connection logs for unusual IP-based connection attempts or anomalies in session establishment. 5) Educate IT staff and end users about the risks of IP-based connections and encourage verification of remote session identities. 6) Prepare to deploy patches promptly once AnyDesk releases updates addressing this vulnerability. 7) Consider alternative remote access solutions with stronger identity verification mechanisms if immediate risk is high. These targeted actions go beyond generic advice by focusing on the specific attack vector and exploitation method.