A memory corruption flaw, stemming from race conditions with incorrect locking (CWE‑362 and CWE‑667), allows an attacker to trigger an unexpected Safari crash by delivering specially crafted web content. The issue is remedied in Safari 26.6.1, iOS 18.7.10 and iPadOS 18.7.10, iOS 26.6.1 and iPadOS 26.6.1, macOS Tahoe 26.6.2, and visionOS 27. The crash leads to a denial of service on the affected device without any code‑execution or data‑exfiltration impact.

Apple iOS devices running versions prior to 18.7.10 or 26.6.1, Apple iPadOS devices running versions prior to 18.7.10 or 26.6.1, Apple macOS Tahoe builds prior to 26.6.2, and Apple visionOS devices running version 27 or earlier are affected. All devices that run Safari on those operating systems are vulnerable.

The vulnerability, a memory corruption involving improper locking (CWE-362, CWE-667), has no known code-execution impact and is limited to a crash that affects availability; the CVSS score is 3.1, indicating low severity. Because the EPSS score is < 1% and it is not listed in the CISA KEV catalog, the likelihood of widespread exploitation appears low. However, malicious actors could craft web pages designed to trigger the crash on vulnerable devices, potentially disrupting services or causing denial of service for users who rely on Safari for critical tasks. The remediation procedure focuses on applying the latest system updates that contain the locking fix.