Arctic Wolf Labs investigated multiple intrusions in June that began by exploiting an authentication bypass in Palo Alto Networks PAN-OS and ended in Qilin ransomware. CVE-2026-0257 affects the portal and gateway components and lets an unauthenticated remote attacker establish a VPN session without valid credentials, but only where authentication override cookies are enabled alongside specific certificate configurations. That narrow precondition makes it easy to assume you are unaffected without checking. The flaw is patched. Because it grants VPN access rather than code execution, the intrusions look like ordinary remote logins at the start, which delays detection until ransomware is deployed.
Palo Alto Networks has confirmed that CVE-2026-0257 (CVSS 7.8), a GlobalProtect authentication-bypass flaw in PAN-OS and Prisma Access, is under active exploitation. The flaw lets attackers bypass authentication and establish an unauthorized VPN connection; it affects firewalls with a GlobalProtect portal or gateway when authentication-override cookies are enabled and a specific certificate configuration exists. Rapid7 identified successful exploitation across numerous customers dating back to May 17, with a second wave on May 21, attributed to the same threat actor; in two cases the attacker received a VPN IP and reached the internal network. CISA added the CVE to its KEV catalog on May 29.
Palo Alto Networks confirmed Wednesday that attackers are exploiting a zero-day in its firewall login portal to run code as root on PA-Series and VM-Series firewalls. CVE-2026-0300 (CVSS 9.3) is a buffer overflow in the User-ID Authentication Portal (Captive Portal) that lets unauthenticated attackers send crafted packets and execute code without any login. Palo Alto Unit 42 attributed the activity to CL-STA-1132, a likely state-sponsored cluster that started probing on April 9 and achieved RCE a week later. Attackers deploy tunneling tools and enumerate Active Directory using the firewall's service account. First patches arrive May 13. Shadowserver counts 5,800+ exposed VM-Series firewalls.
TrustStrike Labs