CVE-2026-76753 in ClearPass Policy Manager
Summary
by MITRE • 10/06/2026
A format string vulnerability in an affected service interface of HPE Networking ClearPass Policy Manager could allow an unauthenticated remote attacker to corrupt process memory. Successful exploitation could allow an attacker to execute arbitrary code.
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Analysis
by VulDB Data Team • 10/06/2026
The identified security flaw represents a critical format string vulnerability within the service interfaces of Hewlett Packard Enterprise (HPE) Networking ClearPass Policy Manager, specifically affecting versions prior to 6.12 Patch 3 and 6.10 through 6.11. This type of vulnerability arises when an application fails to properly sanitize user-supplied input before passing it as a format argument to functions such as printf or syslog. In the context of ClearPass Policy Manager, which serves as a central identity management and network access control solution for many enterprise environments, this flaw is particularly severe because it can be exploited by unauthenticated remote attackers. The attacker does not need valid credentials to initiate an exploit, significantly lowering the barrier to entry for malicious actors targeting these systems.
From a technical perspective, format string vulnerabilities occur when user-controlled data is interpreted as part of a command or instruction rather than as static text. When functions like printf process their arguments, they rely on format specifiers such as %s, %x, or %n to determine how to interpret subsequent values in the stack. If an attacker injects these specifiers into input fields that are subsequently passed directly to formatting functions without validation, the application will attempt to read from arbitrary memory locations specified by the attacker. This can lead to information disclosure where sensitive data stored on the process heap or stack is leaked back to the user interface. More critically, if specific write-oriented format strings like %n are utilized, an attacker can overwrite pointers in memory with controlled values.
The operational impact of successfully exploiting this vulnerability extends far beyond simple data leakage. By carefully crafting a sequence of format specifiers and payload data, an unauthenticated remote attacker can achieve arbitrary code execution on the affected system. This means the attacker gains full control over the underlying operating system running ClearPass Policy Manager. Given that ClearPass often manages authentication policies for critical network infrastructure including wireless access points, switches, and firewalls, compromising this service effectively grants the attacker a foothold deep within the enterprise network perimeter. The ability to execute arbitrary code allows for the installation of backdoors, lateral movement to other systems, exfiltration of sensitive credential databases, or disruption of network availability services.
This vulnerability aligns with Common Weakness Enumeration identifier CWE-134, which classifies use of externally-controlled format string as a distinct category of software errors that lead to memory corruption and potential code execution. In terms of the MITRE ATT&CK framework, this exploit technique falls under Tactic TA0002 Execution and specifically Technique T1059 Command and Scripting Interpreter or potentially T1068 Exploitation for Privilege Escalation depending on the specific vector used to gain initial access before code execution. The unauthenticated nature of the attack places it firmly within Remote Code Execution (RCE) scenarios, which are consistently rated as high-severity due to their direct impact on system integrity and confidentiality.
Mitigation strategies must prioritize immediate patching if available from HPE support channels for the specific version in use. Organizations should ensure that all ClearPass Policy Manager instances are updated to versions 6.12 Patch 3 or later, or 6.10 through 6.11 with the appropriate security patches applied as released by the vendor. In environments where patching is not immediately feasible due to operational constraints, network segmentation becomes a critical compensating control. The service interfaces susceptible to this vulnerability should be restricted from direct internet access and limited to trusted management networks only. Additionally, deploying intrusion detection or prevention systems with signatures capable of detecting format string attack patterns can provide an additional layer of defense by blocking malicious payloads before they reach the vulnerable application logic. Regular auditing of input validation practices across all custom integrations and third-party plugins connected to ClearPass is also recommended to prevent similar flaws in extended functionality modules.