CVE-2023-42940 is a vulnerability identified in Apple macOS that arises from a session rendering issue during screen sharing sessions. Specifically, when a user initiates screen sharing, the system may incorrectly track the session content, causing the user to unintentionally share content other than what they intended. This flaw is categorized under CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor), indicating a confidentiality breach. The vulnerability requires local privileges (PR:L) and user interaction (UI:R), meaning the user must actively share their screen for the issue to manifest. The attack vector is network-based (AV:N), as screen sharing typically occurs over network connections. The CVSS 3.1 base score is 5.7 (medium severity), reflecting a high confidentiality impact but no impact on integrity or availability. The vulnerability affects unspecified versions of macOS prior to the release of macOS Sonoma 14.2.1, which includes the fix via improved session tracking mechanisms. No known exploits are currently in the wild, but the risk remains for accidental data leakage during remote meetings or presentations. The vulnerability primarily threatens confidentiality by potentially exposing sensitive or private information unintentionally shared during screen sharing sessions. This could include proprietary business data, personal information, or other confidential content. The flaw does not allow an attacker to alter data or disrupt system availability, limiting its impact to information exposure only.

For European organizations, this vulnerability poses a significant risk to confidentiality, especially in sectors relying heavily on remote collaboration and screen sharing, such as finance, legal, healthcare, and technology. Unintended exposure of sensitive information could lead to data breaches, regulatory non-compliance (e.g., GDPR violations), reputational damage, and potential financial penalties. The risk is amplified in environments where macOS devices are prevalent and used for critical communications or presentations. Since the vulnerability requires user interaction and local privileges, the likelihood of exploitation is somewhat mitigated; however, accidental data leaks remain a concern. Organizations with hybrid or remote workforces are particularly vulnerable, as screen sharing is a common practice. The absence of known exploits reduces immediate threat levels but does not eliminate the risk of inadvertent information disclosure. The vulnerability does not affect system integrity or availability, so operational disruptions are unlikely. However, the confidentiality breach could have cascading effects on trust and compliance within European regulatory frameworks.

European organizations should prioritize updating all macOS devices to version Sonoma 14.2.1 or later, where the vulnerability is patched. IT departments should implement strict patch management policies to ensure timely deployment of security updates. User training is critical: educate employees on the risks of screen sharing, emphasizing the importance of verifying shared content before initiating sessions. Implement technical controls such as restricting screen sharing capabilities to trusted applications and users, and consider using virtual desktop infrastructure (VDI) solutions that provide better session isolation. Organizations can also deploy Data Loss Prevention (DLP) tools that monitor and alert on sensitive data exposure during screen sharing. Regular audits of remote collaboration tools and usage policies should be conducted to identify and mitigate risks. Additionally, consider disabling screen sharing features where not essential or using alternative secure communication methods. Monitoring network traffic for unusual screen sharing activity can help detect potential misuse. Finally, maintain an incident response plan that includes procedures for accidental data exposure scenarios.