Adobe Patches Actively Exploited Zero-Day That Lingered for Months

Adobe patched CVE-2026-34621, a high-severity zero-day in Acrobat and Reader exploited in the wild via highly obfuscated PDFs that execute on open to fingerprint victims, steal files and system information, and can stage subsequent remote code execution or sandbox escape payloads; researcher Haifei Li traced samples on VirusTotal (as far back as Nov 28, 2025) and Adobe confirmed exploitation, advising immediate updates and monitoring for the 'Adobe Synchronizer' User-Agent string.