Qilin Ransomware Attackers Exploit PAN-OS Authentication Bypass for Initial Access

Threat actors are exploiting a high-severity vulnerability in Palo Alto Networks PAN-OS to gain initial access to environments and deploy Qilin ransomware. The vulnerability, which has been patched, is an authentication bypass flaw that affects the portal and gateway. It was exploited in multiple intrusions investigated by Arctic Wolf Labs in June 2026. The vulnerability has a CVSS score of 7.8, indicating a significant level of severity. The exploitation of this flaw allows attackers to deploy Qilin ransomware on victim environments.