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.
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