Palo Alto PAN-OS Flaw Under Active Exploitation Enables Remote Code Execution

Palo Alto PAN-OS Flaw Under Active Exploitation Enables Remote Code Execution Ravie LakshmananMay 06, 2026Vulnerability / Network Security Palo Alto Networks has released an advisory warning that a critical buffer overflow vulnerability in its PAN-OS software has been exploited in the wild. The vulnerability, tracked as CVE-2026-0300, has been described as a case of unauthenticated remote code execution. It carries a CVSS score of 9.3 if the User-ID Authentication Portal is configured to enable access from the internet or any untrusted network. The severity comes down to 8.7 if access to the portal is restricted to only trusted internal IP addresses. "A buffer overflow vulnerability in the User-ID Authentication Portal (aka Captive Portal) service of Palo Alto Networks PAN-OS software allows an unauthenticated attacker to execute arbitrary code with root privileges on the PA-Series and VM-Series firewalls by sending specially crafted packets," the company said. According to Palo Alto Networks, the vulnerability has come under "limited exploitation," specifically targeting instances where the User-ID Authentication Portal has been left publicly accessible. The following versions are impacted by the flaw - PAN-OS 12.1 - < 12.1.4-h5, < 12.1.7 PAN-OS 11.2 - < 11.2.4-h17, < 11.2.7-h13, < 11.2.10-h6, < 11.2.12 PAN-OS 11.1 - < 11.1.4-h33, < 11.1.6-h32, < 11.1.7-h6, < 11.1.10-h25, < 11.1.13-h5, < 11.1.15 PAN-OS 10.2 - < 10.2.7-h34, < 10.2.10-h36, < 10.2.13-h21, < 10.2.16-h7, < 10.2.18-h6 The issue, as it stands, is unpatched, with Palo Alto Networks planning to release fixes starting May 13, 2026. The company also said the vulnerability is applicable only to PA-Series and VM-Series firewalls that are configured to use the User-ID Authentication Portal.  "Customers following standard security best practices, such as restricting sensitive portals to trusted internal networks are at a greatly reduced risk," it added. In the absence of a patch, users are advised to either restrict User-ID Authentication Portal access to only trusted zones, or disable it entirely, if it's not required. Found this article interesting? Follow us on Google News, Twitter and LinkedIn to read more exclusive content we post. SHARE     Tweet Share Share SHARE  cybersecurity, Firewall, network security, Palo Alto Networks, remote code execution, Threat Intelligence, Vulnerability, zero day ⚡ Top Stories This Week Bitwarden CLI Compromised in Ongoing Checkmarx Supply Chain Campaign Chinese Silk Typhoon Hacker Extradited to U.S. Over COVID Research Cyberattacks Vercel Finds More Compromised Accounts in Context.ai-Linked Breach Researchers Discover Critical GitHub CVE-2026-3854 RCE Flaw Exploitable via Single Git Push ⚡ Weekly Recap: Fast16 Malware, XChat Launch, Federal Backdoor, AI Employee Tracking and More Checkmarx Confirms GitHub Repository Data Posted on Dark Web After March 23 Attack Harvester Deploys Linux GoGra Backdoor in South Asia Using Microsoft Graph API Apple Fixes iOS Flaw That Let FBI Recover Deleted Signal Messages Microsoft Patches Entra ID Role Flaw That Enabled Service Principal Takeover ThreatsDay Bulletin: $290M DeFi Hack, macOS LotL Abuse, ProxySmart SIM Farms +25 New Stories Researchers Uncover Pre-Stuxnet ‘fast16’ Malware Targeting Engineering Software LMDeploy CVE-2026-33626 Flaw Exploited Within 13 Hours of Disclosure FIRESTARTER Backdoor Hit Federal Cisco Firepower Device, Survives Security Patches Malicious KICS Docker Images and VS Code Extensions Hit Checkmarx Supply Chain Microsoft Confirms Active Exploitation of Windows Shell CVE-2026-32202 Critical cPanel Authentication Vulnerability Identified — Update Your Server Immediately Load More ▼ ⭐ Featured Resources [Guide] Learn a Practical Framework to Evaluate AI Tools for Production Learn How Hidden Identity Blind Spots Weaken Your Security Systems [Webinar] Stop Chasing Alerts and Start Focusing on Real Exposures [Guide] How to Enable Secure Data Movement Without Added Risk