CVE-2025-48986 is an authorization bypass vulnerability identified in Revive Adserver versions 5.5.2, 6.0.1, and earlier. The flaw allows an attacker who is already authenticated to bypass access controls and modify other users' email addresses. This unauthorized modification facilitates account takeover by enabling the attacker to trigger the forgot password functionality, which typically sends password reset links to the registered email address. By changing the victim's email to one controlled by the attacker, they can reset the victim's password and gain full control over their account. The vulnerability stems from improper enforcement of authorization checks (CWE-284) within the application logic. The CVSS v3.0 score of 8.8 reflects the high impact on confidentiality, integrity, and availability, combined with low attack complexity and no requirement for user interaction. Although no public exploits have been reported yet, the vulnerability's nature makes it a critical risk for environments relying on Revive Adserver for managing digital advertising campaigns, as compromised accounts could lead to manipulation of ad content, data leakage, or further network compromise.

For European organizations, the impact of this vulnerability can be significant. Revive Adserver is widely used by digital marketing agencies, media companies, and enterprises managing their own ad campaigns. Successful exploitation could lead to unauthorized access to sensitive advertising data, manipulation of ad delivery, and potential exposure of user or client information. This could damage brand reputation, lead to regulatory non-compliance (e.g., GDPR violations due to unauthorized data access), and cause financial losses. Additionally, compromised accounts could be leveraged as footholds for further attacks within the network, increasing the risk of broader security incidents. The disruption of ad services could also impact revenue streams for companies dependent on online advertising. Given the high CVSS score and the critical nature of the affected systems, European entities must prioritize remediation to mitigate these risks.

Organizations should immediately verify their Revive Adserver versions and upgrade to patched releases once available. In the absence of official patches, administrators should implement strict access controls and monitor user account changes closely. Restricting login access to trusted personnel and enabling multi-factor authentication (MFA) can reduce the risk of attacker login. Additionally, auditing logs for unusual email change requests or password resets can help detect exploitation attempts early. Network segmentation of the ad server environment and limiting its access to essential personnel and systems will reduce the attack surface. If possible, temporarily disabling the forgot password functionality or adding additional verification steps for email changes can serve as interim mitigations. Finally, educating users about phishing and suspicious account activity can help prevent attackers from leveraging compromised credentials.