CVE-2026-0288 in PAN-OS
Summary
by MITRE • 07/08/2026
Multiple buffer overflow vulnerabilities in the User-ID Terminal Server Agent (TSA) component of Palo Alto Networks PAN-OS software allow an unauthenticated attacker with network access to cause a denial of service (DoS) condition or potentially execute arbitrary code by sending specially crafted network traffic.
The security risk posed by this issue is minimized when the User-ID Terminal Server Agent connectivity is restricted to only trusted internal IP addresses according to our recommended best practice deployment guidelines https://docs.paloaltonetworks.com/ngfw/help/10-2/user-identification/device-user-identification-terminal-services-agents#:~:text=To%20minimize%20security%20risk%2C%20restrict%20TS%20Agent%20connectivity%20to%20trusted%20internal%20IP%20addresses%20only. .
Panorama is not impacted by this vulnerability.
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Analysis
by VulDB Data Team • 07/08/2026
The vulnerability under discussion represents a critical buffer overflow condition within the User-ID Terminal Server Agent component of Palo Alto Networks PAN-OS software, classified as CVE-2023-XXXX. This flaw exists in the TSA module responsible for terminal services agent connectivity and user identification functions within the network security platform. The vulnerability manifests when the system processes specially crafted network traffic without adequate input validation or buffer size checking mechanisms.
Buffer overflow conditions in network services represent a fundamental security weakness that can lead to either denial of service or arbitrary code execution depending on the specific implementation details. The technical flaw occurs when the TSA component fails to properly validate incoming data lengths before copying them into fixed-size buffers, creating an opportunity for attackers to overwrite adjacent memory locations. This type of vulnerability maps directly to CWE-121 Buffer Copy without Checking Size of Input and is commonly associated with the attack patterns documented in MITRE ATT&CK framework under T1499.004 for Network Denial of Service and potentially T1059 for Command and Scripting Interpreter if exploitation leads to code execution.
The operational impact of this vulnerability extends beyond simple service disruption, as it provides attackers with potential pathways for system compromise when the TSA functionality is enabled and accessible from untrusted networks. An unauthenticated attacker with network access can craft malicious packets that trigger the buffer overflow condition, potentially causing the affected process to crash and restart, thereby creating a denial of service scenario. More critically, if properly crafted, such attacks could potentially allow attackers to inject and execute arbitrary code within the system context, particularly when the TSA agent is configured to accept connections from external sources.
The security posture of affected systems is significantly weakened when the User-ID Terminal Server Agent connectivity is not properly restricted to trusted internal IP addresses as recommended by Palo Alto Networks best practice guidelines. This restriction serves as a crucial defensive control that limits the attack surface and reduces the likelihood of exploitation, particularly in environments where the TSA functionality is enabled for legitimate user identification purposes but not required from external networks. The vulnerability affects PAN-OS versions where the TSA component remains active, though Panorama management systems are specifically excluded from this particular vulnerability, indicating it's limited to the device-level processing components rather than the centralized management infrastructure.
Organizations should implement immediate network segmentation controls to restrict TSA agent connectivity to only trusted internal IP addresses as specified in Palo Alto Networks recommended deployment guidelines. This restriction effectively limits the exposure window for exploitation and aligns with established security principles of least privilege access. The implementation of these controls directly addresses the attack vectors identified in MITRE ATT&CK framework and provides defense-in-depth measures against the specific buffer overflow conditions that could lead to system compromise or service disruption.