PAN-OS User-ID Authentication Portal buffer overflow, unauthenticated root RCE (CVSS 4.0 9.3), exploited by CL-STA-1132, CISA KEV 2026-05-06; fixed builds on every supported branch

Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network. The weakness in the system can be a software bug, a temporary glitch, or a misconfiguration.

Evidence: 2026-05-12/palo-alto-pan-os-cve-2026-0300-first-wave-fixed-builds-now-s · ATT&CK page ↗

Adversaries may inject code into processes in order to evade process-based defenses as well as possibly elevate privileges. Process injection is a method of executing arbitrary code in the address space of a separate live process. Running code in the context of another process may allow access to the process's memory, system/network resources, and possibly elevated privileges. Execution via process injection may also evade detection from security products since the execution is masked under a legitimate process.

Evidence: 2026-05-12/palo-alto-pan-os-cve-2026-0300-first-wave-fixed-builds-now-s · ATT&CK page ↗

Adversaries may inject code into processes in order to evade process-based defenses as well as possibly elevate privileges. Process injection is a method of executing arbitrary code in the address space of a separate live process. Running code in the context of another process may allow access to the process's memory, system/network resources, and possibly elevated privileges. Execution via process injection may also evade detection from security products since the execution is masked under a legitimate process.

Evidence: 2026-05-12/palo-alto-pan-os-cve-2026-0300-first-wave-fixed-builds-now-s · ATT&CK page ↗

Adversaries may selectively delete or modify artifacts generated to reduce indications of their presence and blend in with legitimate activity. Rather than broadly removing evidence, adversaries may target specific artifacts that appear anomalous or are likely to draw scrutiny, while leaving sufficient data intact to maintain the appearance of normal system behavior.

Evidence: 2026-05-12/palo-alto-pan-os-cve-2026-0300-first-wave-fixed-builds-now-s · ATT&CK page ↗

Adversaries may attempt to get a listing of domain accounts. This information can help adversaries determine which domain accounts exist to aid in follow-on behavior such as targeting specific accounts which possess particular privileges.

Evidence: 2026-05-12/palo-alto-pan-os-cve-2026-0300-first-wave-fixed-builds-now-s · ATT&CK page ↗

Adversaries may use a connection proxy to direct network traffic between systems or act as an intermediary for network communications to a command and control server to avoid direct connections to their infrastructure. Many tools exist that enable traffic redirection through proxies or port redirection, including HTRAN, ZXProxy, and ZXPortMap. Adversaries use these types of proxies to manage command and control communications, reduce the number of simultaneous outbound network connections, provide resiliency in the face of connection loss, or to ride over existing trusted communications paths between victims to avoid suspicion. Adversaries may chain together multiple proxies to further disguise the source of malicious traffic.

Evidence: 2026-05-12/palo-alto-pan-os-cve-2026-0300-first-wave-fixed-builds-now-s · ATT&CK page ↗

Adversaries may tunnel network communications to and from a victim system within a separate protocol to avoid detection/network filtering and/or enable access to otherwise unreachable systems. Tunneling involves explicitly encapsulating a protocol within another. This behavior may conceal malicious traffic by blending in with existing traffic and/or provide an outer layer of encryption (similar to a VPN). Tunneling could also enable routing of network packets that would otherwise not reach their intended destination, such as SMB, RDP, or other traffic that would be filtered by network appliances or not routed over the Internet.

Evidence: 2026-05-12/palo-alto-pan-os-cve-2026-0300-first-wave-fixed-builds-now-s · ATT&CK page ↗