CVE-2025-43376 is a vulnerability identified in Apple Safari's Private Relay feature, which is designed to enhance user privacy by encrypting DNS queries and routing them through Apple’s proxy servers. The vulnerability arises from a logic flaw in state management within Safari’s DNS handling process when Private Relay is enabled. This flaw allows a remote attacker to bypass the intended privacy protections and view DNS queries that should otherwise be concealed. The issue affects Safari 26 and corresponding Apple operating system versions including iOS 18.7.7, iPadOS 18.7.7, macOS Tahoe 26, tvOS 26, visionOS 26, and watchOS 26. The vulnerability is exploitable remotely without requiring any user interaction or privileges, making it particularly dangerous. The CVSS v3.1 score of 7.5 reflects a high severity due to the ease of exploitation (network vector, low attack complexity, no privileges or user interaction required) and the high confidentiality impact, as DNS queries can reveal user browsing habits and potentially sensitive information. Apple has resolved this issue through improved state management in the affected software versions. No known exploits have been reported in the wild so far, but the potential for privacy breaches is significant, especially for users relying on Private Relay for enhanced anonymity.

The primary impact of CVE-2025-43376 is the compromise of user privacy through the leakage of DNS queries that are supposed to be protected by Apple’s Private Relay. DNS queries can reveal detailed information about user browsing behavior, visited websites, and potentially sensitive or confidential activities. For organizations, this leakage could expose employee browsing patterns, internal resource access attempts, or other sensitive operational details. Since the vulnerability can be exploited remotely without authentication or user interaction, attackers can surveil users on vulnerable devices at scale. This undermines trust in Apple’s privacy features and could lead to targeted surveillance, profiling, or data harvesting by malicious actors. The vulnerability affects a broad range of Apple devices, including desktops, laptops, mobile devices, and IoT platforms, increasing the scope of potential impact. Although no integrity or availability impacts are noted, the confidentiality breach is significant, especially for privacy-conscious users and organizations handling sensitive data.

To mitigate CVE-2025-43376, organizations and users should promptly update all affected Apple devices to the patched versions: Safari 26, iOS 18.7.7 and iPadOS 18.7.7, macOS Tahoe 26, tvOS 26, visionOS 26, and watchOS 26. It is critical to enforce update policies that ensure timely deployment of these patches across all managed devices. Network administrators should monitor DNS traffic for unusual patterns that may indicate exploitation attempts. Where feasible, consider additional DNS privacy measures such as DNS over HTTPS (DoH) or DNS over TLS (DoT) as complementary protections. For high-security environments, temporarily disabling Private Relay until patches are applied may be warranted. Security teams should also educate users about the importance of applying updates and the risks of using unpatched software. Finally, organizations should review their threat detection capabilities to identify potential reconnaissance activities targeting DNS traffic on Apple devices.