Executive brief
macOS includes core certificate validation mechanisms that protect users from man-in-the-middle attacks when connecting to secure services like banking and email. A flaw in certificate validation could allow an attacker on the same network to intercept encrypted traffic and impersonate legitimate services, compromising user data and system security.
Technical details
A certificate validation issue in macOS allows an attacker in a privileged network position to intercept network traffic. The vulnerability was addressed through improved certificate validation routines. The attack vector requires network adjacency (MITM position on the same network segment). No user interaction or authentication is required. An attacker can perform traffic interception and spoofing attacks against applications relying on TLS certificate validation. The patch is available in macOS Golden Gate 27, macOS Sequoia 15.8, and macOS Tahoe 26.7.
Affected products
- Apple macOS Golden Gate before 27
- Apple macOS Sequoia before 15.8
- Apple macOS Tahoe before 26.7
Timeline
- 2026-09-14: disclosed
- 2026-09-14: patched