CVE-2022-41971 is a vulnerability affecting the Nextcloud Talk Android application, which is used for video and audio conferencing within the Nextcloud ecosystem. The flaw exists in versions prior to 12.2.8, 13.0.10, 14.0.6, and 15.0.0. The vulnerability allows a guest participant, who has been removed from a public conversation during an ongoing call, to continue receiving video streams from that call. This means that even after removal, the attacker can still view live video feeds, leading to unauthorized exposure of private personal information. The issue arises because the application fails to properly terminate the video stream to the removed user, violating expected access control and session management protocols. The vulnerability is categorized under CWE-359 (Exposure of Private Personal Information to an Unauthorized Actor) and CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor). There are no known workarounds, but patches have been released in the specified versions to address the issue. No known exploits have been reported in the wild as of the published date.

For European organizations using Nextcloud Talk Android for internal or external communications, this vulnerability poses a significant privacy risk. Unauthorized users who are removed from a call can still observe sensitive video content, potentially exposing confidential meetings, personal data, or strategic discussions. This could lead to breaches of GDPR regulations due to unauthorized data exposure, resulting in legal and financial repercussions. The impact is particularly critical for sectors handling sensitive information such as healthcare, finance, government, and legal services. Additionally, the breach of confidentiality could undermine trust in communication platforms and disrupt business operations. Since the vulnerability affects public conversations, organizations relying on public or semi-public conferencing may be more vulnerable. The lack of known exploits in the wild reduces immediate risk but does not eliminate the threat, especially if attackers reverse-engineer the vulnerability from the disclosed details.

Organizations should immediately update Nextcloud Talk Android clients to versions 12.2.8, 13.0.10, 14.0.6, 15.0.0, or later to apply the official patches. Until updates are deployed, administrators should restrict the use of public conversations or disable guest access to calls to minimize exposure. Implement strict access controls and monitor call participant lists actively to detect unauthorized presence. Employ network-level monitoring to detect anomalous streaming activity that could indicate unauthorized video reception. Additionally, organizations should review and reinforce their data protection policies to ensure compliance with GDPR and other privacy regulations. User training should emphasize the risks of guest participation in sensitive calls and encourage reporting of suspicious behavior. Finally, consider segregating sensitive meetings to private conversations with authenticated participants only, reducing the attack surface.