Adobe issues emergency fix for Acrobat Reader flaw exploited in the wild (CVE-2026-34621)

**Executive Summary:** Adobe has released an emergency security update for CVE-2026-34621, a critical prototype-pollution zero-day in Acrobat/Reader actively exploited via malicious PDFs that can perform system fingerprinting, contact attacker C2 infrastructure and potentially load further exploits; administrators should apply the provided patches immediately and implement recommended mitigations (avoid opening untrusted PDFs, monitor endpoints, and block traffic with the "Adobe Synchronizer" User-Agent string).