CVE-2026-76722: HPE Networking Instant ON APs RCE Vulnerability

CVE-2026-76722 Overview

CVE-2026-76722 is an uncontrolled format string vulnerability affecting HPE Networking Instant ON access points. An unauthenticated remote attacker can send crafted input to the affected interface to execute arbitrary commands on the underlying host. Successful exploitation results in denial of service or remote code execution on the wireless access point.

The vulnerability requires no authentication, no user interaction, and can be triggered across the network. It compromises the confidentiality, integrity, and availability of the access point and any network segment it serves.

Critical Impact
Unauthenticated remote attackers can execute arbitrary commands on HPE Networking Instant ON APs, enabling full device compromise, lateral movement, and disruption of wireless network services.

Affected Products

HPE Networking Instant ON Access Points
Refer to the HPE Security Bulletin for the specific firmware versions impacted
Deployments exposing the affected management interface to untrusted networks

Discovery Timeline

2026-09-29 - CVE-2026-76722 published to the National Vulnerability Database
2026-09-29 - Last updated in NVD database

Technical Details for CVE-2026-76722

Vulnerability Analysis

The flaw is an uncontrolled format string vulnerability [CWE-134] in an exposed interface of HPE Networking Instant ON access points. The affected component passes attacker-supplied input directly to a formatted output function without sanitization or a fixed format specifier.

When a function such as printf, syslog, or a vendor logging helper receives user input as the format argument, conversion specifiers embedded in that input are interpreted at runtime. Attackers can use specifiers like %x, %s, and %n to read process memory, disclose stack contents, or write to arbitrary memory addresses. On embedded network devices, this typically leads to service crashes or command execution under the daemon's privileges.

Because the affected interface accepts unauthenticated network traffic, exploitation does not require prior credentials or user interaction. The attacker only needs network reach to the vulnerable service on the access point.

Root Cause

The root cause is improper use of a formatted output function that treats untrusted input as the format string parameter. Secure coding practice requires a constant format string with user data supplied as separate arguments, for example printf("%s", user_input) rather than printf(user_input).

Attack Vector

An attacker sends crafted data containing format specifiers to the vulnerable network-facing interface of the access point. The malformed input triggers memory disclosure, memory corruption, or process termination. Chaining %n writes with careful payload construction can redirect execution flow and achieve arbitrary command execution on the underlying host.

See the HPE Security Bulletin for vendor technical detail.

Detection Methods for CVE-2026-76722

Indicators of Compromise

Unexpected reboots or crash loops on Instant ON access points not tied to firmware updates or power events
Outbound connections from access points to unfamiliar hosts, particularly on non-standard ports
Log entries containing raw format specifiers such as %x, %s, %p, or %n in requests to the management interface
New or unauthorized administrative sessions and configuration changes on the AP

Detection Strategies

Inspect network traffic destined for AP management interfaces for payloads containing format specifier sequences
Correlate AP process crash events with inbound traffic bursts from a single source
Baseline outbound connections from access points and alert on deviations, since APs should rarely initiate arbitrary egress

Monitoring Recommendations

Forward AP syslog and crash telemetry to a centralized SIEM for anomaly detection
Monitor firmware integrity and configuration checksums for unauthorized modifications
Alert on management-plane access from source IPs outside approved administrative ranges

How to Mitigate CVE-2026-76722

Immediate Actions Required

Apply the firmware update referenced in the HPE Security Bulletin to all affected Instant ON access points
Restrict access to AP management interfaces to trusted administrative networks only
Audit AP logs and configurations for signs of tampering or prior exploitation
Rotate administrative credentials and pre-shared keys used on affected APs

Patch Information

HPE has published guidance and fixed firmware for HPE Networking Instant ON access points. Refer to the HPE Security Bulletin for the exact fixed versions and upgrade instructions. Deploy the patched firmware across all affected devices before re-exposing management services.

Workarounds

Block network reach to the vulnerable interface at upstream firewalls or ACLs until patching is complete
Isolate access points on a dedicated management VLAN with strict ingress filtering
Disable remote administration features that are not required for operations
Terminate direct internet exposure of AP management ports and require VPN access for administration

bash

# Example ACL restricting AP management access to a trusted subnet
access-list AP-MGMT permit tcp 10.10.0.0 0.0.0.255 host <AP_IP> eq 443
access-list AP-MGMT deny   ip any host <AP_IP>
interface Vlan100
 ip access-group AP-MGMT in