CVE-2025-43366 is a vulnerability identified in Apple macOS involving an out-of-bounds read condition that allows an application to access coprocessor memory beyond its intended bounds. This flaw arises due to insufficient bounds checking in the affected macOS component, classified under CWE-125 (Out-of-bounds Read). The vulnerability enables a local attacker, with no privileges and requiring user interaction, to read sensitive data from the coprocessor memory, potentially disclosing confidential information. The coprocessor memory may contain cryptographic keys, secure enclave data, or other sensitive operational information critical to system security. The issue was addressed by Apple in macOS Tahoe 26 through improved bounds checking to prevent unauthorized memory disclosure. The CVSS v3.1 base score is 5.5 (medium severity), reflecting the local attack vector (AV:L), low attack complexity (AC:L), no privileges required (PR:N), user interaction required (UI:R), unchanged scope (S:U), high confidentiality impact (C:H), and no integrity or availability impact (I:N/A:N). No known exploits have been reported in the wild, but the vulnerability represents a potential risk for data leakage on affected systems. The vulnerability affects all macOS versions prior to the patched release, with no specific version numbers provided beyond the fixed macOS Tahoe 26. The vulnerability's exploitation requires local access and user interaction, limiting remote exploitation but still posing a risk in environments where untrusted apps can be executed.

The primary impact of CVE-2025-43366 is the potential unauthorized disclosure of sensitive coprocessor memory contents, which can include cryptographic keys, secure enclave data, or other protected information. This compromises confidentiality but does not affect system integrity or availability. Organizations relying on macOS devices, especially those handling sensitive or classified information, face increased risk of data leakage if untrusted or malicious applications are executed locally. The requirement for user interaction and local access reduces the likelihood of widespread exploitation but does not eliminate risk in environments with lax endpoint controls or where users may be tricked into running malicious software. The vulnerability could be leveraged in targeted attacks against high-value individuals or organizations to extract sensitive data from coprocessors. The absence of known exploits in the wild currently limits immediate risk, but the medium severity rating and potential impact on confidentiality warrant prompt remediation.

To mitigate CVE-2025-43366, organizations should prioritize updating all macOS devices to macOS Tahoe 26 or later, where the vulnerability is fixed with improved bounds checking. Endpoint security policies should restrict the execution of untrusted or unsigned applications to reduce the risk of local exploitation. Employ application whitelisting and enforce strict user privilege management to limit the ability of unprivileged users to run potentially malicious code. Educate users about the risks of running unknown applications and the importance of user interaction in exploitation scenarios. Monitor local system activity for unusual behavior that could indicate attempts to exploit memory disclosure vulnerabilities. For environments with high security requirements, consider additional hardware-based protections or coprocessor isolation features. Regularly review and update security policies to incorporate new patches and threat intelligence related to macOS vulnerabilities.