Apple Patches Persistent Cookie Vulnerability Discovered by Zscaler

Zscaler reported a vulnerability in macOS El Capitan that permitted unprivileged applications to read Safari's persistent cookies, which could allow attackers to impersonate users and access account data (including webmail). Apple mitigated the issue in Security Update 2016-004 for OS X 10.11.6; the advisory also provides background on persistent cookie usage across websites.