CVE-2026-76753 Overview
CVE-2026-76753 is a format string vulnerability in a service interface of HPE Networking ClearPass Policy Manager. An unauthenticated remote attacker can send crafted input that corrupts process memory. Successful exploitation can lead to arbitrary code execution on the affected system.
ClearPass Policy Manager handles network access control, authentication, and policy enforcement in enterprise environments. Compromise of this component exposes authentication workflows and connected network infrastructure. The vulnerability requires no privileges and no user interaction, and it is reachable over the network.
Critical Impact
An unauthenticated remote attacker can corrupt process memory and execute arbitrary code on the ClearPass Policy Manager service, compromising network authentication infrastructure.
Affected Products
- HPE Networking ClearPass Policy Manager (see the vendor advisory for affected versions)
Discovery Timeline
- 2026-10-06 - CVE-2026-76753 published to NVD
- 2026-10-07 - Last updated in NVD database
Technical Details for CVE-2026-76753
Vulnerability Analysis
The flaw is a format string vulnerability [CWE-134] in an exposed service interface of ClearPass Policy Manager. Format string issues occur when user-controlled input is passed directly as the format argument to functions such as printf, sprintf, or syslog instead of being supplied as a data argument.
Attacker-controlled format specifiers like %s, %x, and %n enable reading from and writing to process memory. Repeated writes with %n can overwrite function pointers, return addresses, or Global Offset Table (GOT) entries. Combined with memory layout disclosure, this provides a path to arbitrary code execution in the context of the ClearPass service process.
Because the affected interface is reachable without authentication, attackers do not need credentials or user interaction. The EPSS score is 0.525% with a percentile of 42.707 as of 2026-10-07.
Root Cause
The root cause is improper handling of externally supplied data within a formatted output function. User input reaches the format string parameter directly, allowing attackers to inject conversion specifiers that the function interprets against the process stack and memory.
Attack Vector
The attack vector is network-based. An unauthenticated attacker sends a crafted request containing format specifiers to the vulnerable service interface. The malformed input triggers memory corruption that can be shaped into arbitrary code execution. Refer to the HPE Security Advisory for interface and protocol specifics.
No verified public proof-of-concept code is available at the time of publication. The vulnerability mechanism is described in prose rather than with synthetic exploit code.
Stop Remote Code Execution Before It Runs
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Stop Exploit AttemptsDetection Methods for CVE-2026-76753
Indicators of Compromise
- Unexpected crashes, restarts, or core dumps of ClearPass Policy Manager service processes
- Inbound requests to ClearPass service interfaces containing repeated format specifiers such as %s, %x, %n, or long sequences of %p
- New or unexpected child processes spawned by ClearPass service accounts
- Outbound network connections from ClearPass hosts to untrusted destinations following anomalous inbound traffic
Detection Strategies
- Inspect network traffic to ClearPass management and service interfaces for payloads containing format specifier patterns
- Correlate service crashes with inbound requests from the same source within short time windows
- Baseline process execution on ClearPass hosts and alert on deviations from the expected process tree
- Monitor authentication logs for anomalous administrative actions originating from the ClearPass host itself
Monitoring Recommendations
- Forward ClearPass application, system, and crash logs to a central SIEM or data lake for correlation
- Enable packet capture or network flow logging on segments that reach ClearPass service interfaces
- Alert on repeated connection resets or malformed protocol responses from ClearPass services
How to Mitigate CVE-2026-76753
Immediate Actions Required
- Apply the vendor-supplied patch referenced in the HPE Security Advisory as the primary remediation
- Restrict network access to ClearPass Policy Manager service interfaces to trusted management networks and administrative hosts
- Inventory ClearPass deployments and confirm each instance against the vendor advisory to determine patch status
- Review service and authentication logs for signs of exploitation attempts preceding patch deployment
Patch Information
HPE has published fixed versions through the official security advisory. Consult the HPE Security Advisory for affected version ranges, patched releases, and upgrade instructions. Apply updates to all ClearPass Policy Manager nodes, including cluster subscribers.
Workarounds
- Place ClearPass service interfaces behind firewall rules that allow access only from known administrative networks
- Terminate exposure of the affected interface at a reverse proxy or network access control device when patching cannot be scheduled immediately
- Increase monitoring sensitivity on ClearPass hosts until patches are applied cluster-wide
# Example: restrict access to ClearPass service interfaces at the network layer
# Replace CLEARPASS_IP, ADMIN_SUBNET, and SERVICE_PORT with environment values
iptables -A INPUT -p tcp -s ADMIN_SUBNET -d CLEARPASS_IP --dport SERVICE_PORT -j ACCEPT
iptables -A INPUT -p tcp -d CLEARPASS_IP --dport SERVICE_PORT -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
