A use‑after‑free flaw in the memory handling of Apple web browsers can be triggered by a malicious web extension, potentially causing the process to crash unexpectedly, which results in loss of service for the user or a compromised user experience. The flaw stems from premature deallocation of memory objects used by extensions, which can lead to undefined behavior. While the crash does not provide direct code execution or data exfiltration, it results in denial of service and negative user impact.

Apple Safari on macOS, as well as the iOS and iPadOS platforms, are affected. Versions prior to 26.5.2 of Safari, iOS, iPadOS, and macOS Tahoe contain the vulnerability. The issue is fixed in Safari 26.5.2, iOS 26.5.2, iPadOS 26.5.2, and macOS Tahoe 26.5.2.

The EPSS metric is not available, and the vulnerability is not listed in CISA's KEV catalog, indicating no known active exploitation at the time of this report. However, the flaw can be exploited by any malicious web extension, which is a common vector for browser attacks. No CVSS score is provided in the data, but the impact of a crash is significant for availability and user trust.