CVE-2025-43390 is a vulnerability identified in Intel-based Apple macOS systems, specifically addressed in macOS Sequoia 15.7.2 and macOS Tahoe 26.1. The root cause is a downgrade issue involving code-signing restrictions, which are mechanisms macOS uses to verify the integrity and authenticity of applications. This vulnerability allows a malicious application to bypass these restrictions and access sensitive user data that it should not normally be able to access. The vulnerability does not require elevated privileges (PR:N) but does require user interaction (UI:R), such as running or installing the malicious app. The attack vector is local (AV:L), meaning an attacker must have local access to the machine. The vulnerability impacts confidentiality (C:H) but does not affect integrity or availability. The underlying weakness corresponds to CWE-347, which relates to improper verification of cryptographic signatures, in this case, code signatures. Apple mitigated this issue by implementing stricter code-signing enforcement to prevent downgrade attacks that could allow older, less secure code-signing policies to be exploited. No public exploits or active exploitation in the wild have been reported to date. The vulnerability highlights the importance of robust code-signing policies to maintain application security on macOS platforms.

The primary impact of CVE-2025-43390 is unauthorized access to sensitive user data on affected Intel-based macOS systems. This breach of confidentiality could lead to exposure of personal information, credentials, or other sensitive files stored or accessible on the device. Although the vulnerability does not affect system integrity or availability, the data exposure risk could facilitate further attacks such as identity theft, phishing, or targeted espionage. The requirement for local access and user interaction limits the scope of exploitation, reducing the likelihood of widespread automated attacks. However, organizations with many Intel-based Macs, especially those handling sensitive or regulated data, face increased risk if users inadvertently run malicious applications exploiting this flaw. The vulnerability could be leveraged by insider threats or attackers who gain physical or remote access to user machines. Failure to patch could result in data breaches, regulatory non-compliance, and reputational damage.

To mitigate CVE-2025-43390, organizations should prioritize updating all Intel-based macOS systems to macOS Sequoia 15.7.2 or macOS Tahoe 26.1 or later, where the vulnerability is fixed. Enforce strict application installation policies, such as restricting app installations to those from the Mac App Store or identified developers with valid code signatures. Implement endpoint protection solutions capable of detecting suspicious local application behavior and code-signing anomalies. Educate users about the risks of running untrusted applications and the importance of verifying app sources before installation or execution. Employ device management tools to monitor and control software installations and enforce patch compliance. Regularly audit systems for outdated macOS versions and unauthorized software. Consider additional data protection measures such as encryption and access controls to limit the impact of potential data exposure. Finally, maintain robust incident response plans to quickly address any suspected exploitation.