CVE-2025-20291 is a medium-severity vulnerability identified in Cisco Webex Meetings, a widely used video conferencing platform. The vulnerability is classified as an 'Open Redirect' issue, where insufficient validation of URLs embedded within meeting-join links allows an unauthenticated remote attacker to redirect targeted users to arbitrary, untrusted websites. Specifically, the flaw arises because the Webex Meetings service does not properly validate the URL parameters included in the meeting join URL. An attacker could craft a malicious join URL containing a redirect to a site under their control. When a user clicks this manipulated link, they are redirected away from the legitimate Webex domain to the attacker’s site. This redirection could be leveraged to facilitate phishing attacks by exploiting the user's trust in Webex, potentially leading to credential theft or malware delivery. The vulnerability requires no authentication but does require user interaction (clicking the malicious link). Cisco has addressed this issue within the Webex Meetings service itself, and no customer-side patching or action is required. The CVSS v3.1 base score is 4.3 (medium), reflecting the network attack vector, low complexity, no privileges required, user interaction needed, and limited impact on integrity without affecting confidentiality or availability. There are no known exploits in the wild at this time.

For European organizations, this vulnerability poses a risk primarily in the context of social engineering and phishing campaigns. Since Webex Meetings is extensively used across Europe for business communications, education, and government operations, attackers could exploit this flaw to redirect users to malicious sites that mimic legitimate services or harvest credentials. The impact on confidentiality is limited to the potential theft of user credentials or sensitive information entered on phishing sites. Integrity could be compromised if users are tricked into executing malicious actions or downloading malware. Availability is not affected by this vulnerability. Given the widespread adoption of Cisco Webex in sectors such as finance, healthcare, and public administration in Europe, successful exploitation could lead to targeted spear-phishing campaigns, increasing the risk of data breaches or unauthorized access. However, the requirement for user interaction and the medium severity score suggest that the threat is moderate and can be mitigated with proper user awareness and technical controls.

Although Cisco has remediated this vulnerability on the server side, European organizations should implement additional mitigations to reduce risk. First, conduct targeted user awareness training focusing on recognizing suspicious URLs and the risks of clicking unknown links, especially in meeting invitations. Second, deploy email security solutions with URL rewriting and sandboxing capabilities to detect and block malicious links before they reach users. Third, implement web filtering solutions that can block access to known malicious domains or suspicious redirectors. Fourth, encourage the use of multi-factor authentication (MFA) on Webex accounts to reduce the impact of credential theft. Fifth, monitor Webex meeting join URLs in internal communications for anomalies or unexpected redirects. Finally, maintain up-to-date threat intelligence feeds to identify emerging phishing campaigns exploiting this vulnerability.