CVE-2021-1861: Apple macOS

Medium severity, CVSS 4.3. EPSS: 0.9% chance of exploitation in the next 30 days.

An issue existed in determining cache occupancy. The issue was addressed through improved logic. This issue is fixed in macOS Big Sur 11.3. A malicious website may be able to track users by setting state in a cache.

Affected products

• Apple macOS: from 11.0, before 11.3 (fixed in 11.3)

Published 2021-09-08. Last modified 2026-06-17.