CVE-2025-9870 is a high-severity local privilege escalation vulnerability affecting Razer Synapse 3, version 3.10.228.21112. The vulnerability resides in the Philips HUE module installer component, which improperly resolves symbolic links before performing file operations, classified under CWE-59 (Improper Link Resolution Before File Access). An attacker who already has the ability to execute code with low privileges on the affected system can exploit this flaw by creating a symbolic link that points to arbitrary files. When the installer runs, it follows the symbolic link and deletes files that the attacker targets. This improper handling allows the attacker to escalate privileges from a low-privileged user to SYSTEM level, enabling arbitrary code execution with the highest system privileges. The vulnerability does not require user interaction and has a CVSS 3.0 base score of 7.8, indicating a high impact on confidentiality, integrity, and availability. The attack vector is local, requiring the attacker to have some initial foothold on the system. No public exploits or widespread exploitation have been reported yet. The vulnerability was reserved on 2025-09-02 and published on 2025-10-29. The lack of available patches at the time of reporting means affected users must rely on interim mitigations until official fixes are released. This vulnerability is tracked as ZDI-CAN-26375 by the Zero Day Initiative.

For European organizations, the impact of CVE-2025-9870 can be significant, especially in environments where Razer Synapse 3 is deployed on workstations or systems with sensitive data or critical operations. Successful exploitation allows attackers who have already compromised a low-privileged account to escalate privileges to SYSTEM, effectively gaining full control over the affected machine. This can lead to unauthorized access to confidential information, manipulation or destruction of data, and disruption of services. In corporate or government environments, such privilege escalation can facilitate lateral movement, persistence, and deployment of further malware or ransomware. The vulnerability's local attack vector means that initial compromise is a prerequisite, but once achieved, the attacker can bypass many security controls that rely on privilege separation. Given the popularity of Razer hardware and software among gaming and creative professionals, organizations with such user bases may face increased risk. The absence of known exploits in the wild currently reduces immediate risk but does not eliminate the threat, as attackers may develop exploits rapidly after disclosure.

To mitigate CVE-2025-9870 effectively, European organizations should implement the following specific measures: 1) Restrict local user permissions rigorously to prevent unauthorized code execution at low privilege levels, including applying the principle of least privilege to all user accounts. 2) Monitor and audit filesystem changes, especially the creation of symbolic links in directories accessed by Razer Synapse 3 installers or related modules, to detect suspicious activity early. 3) Temporarily disable or uninstall the Philips HUE module within Razer Synapse 3 if it is not essential to operations, reducing the attack surface. 4) Employ application whitelisting and endpoint protection solutions capable of detecting and blocking attempts to exploit symbolic link vulnerabilities or unauthorized file deletions. 5) Maintain up-to-date backups of critical data to enable recovery in case of successful exploitation. 6) Stay alert for official patches or updates from Razer and apply them promptly once available. 7) Educate users about the risks of running untrusted code locally and enforce strict controls on software installation and execution. 8) Consider network segmentation to limit the impact of compromised endpoints. These targeted actions go beyond generic advice by focusing on the specific exploitation mechanism and affected components.