CVE-2026-73776: AOS-CX CLI RCE Vulnerability

CVE-2026-73776 Overview

CVE-2026-73776 is a signature verification bypass vulnerability in the command line interface (CLI) of HPE Aruba Networking AOS-CX. An authenticated attacker with administrative privileges can execute arbitrary code on the underlying operating system when specific preconditions outside the attacker's control are satisfied. The flaw undermines the integrity guarantees that signature verification provides for software components loaded through the CLI. HPE has documented the issue in a vendor security bulletin and released updated AOS-CX firmware.

Critical Impact
Successful exploitation grants arbitrary code execution on the AOS-CX host operating system, breaking the trust boundary between the network operating system and the underlying platform.

Affected Products

HPE Aruba Networking AOS-CX (network operating system for Aruba CX switches)
Refer to the HPE Security Bulletin for the definitive list of affected AOS-CX branches and fixed builds
Specific CPE identifiers were not published in NVD at the time of writing

Discovery Timeline

2026-09-01 - CVE-2026-73776 published to the National Vulnerability Database
2026-09-03 - Last updated in NVD database

Technical Details for CVE-2026-73776

Vulnerability Analysis

The vulnerability resides in the AOS-CX CLI, which performs signature verification on certain artifacts before they are processed by the underlying operating system. A flaw in that verification path allows an authenticated administrator to bypass the integrity check and cause the platform to execute code that would otherwise be rejected. The issue requires local access to the CLI, high privileges, and no user interaction, but the scope change indicates the impact reaches components beyond the CLI boundary itself. Because AOS-CX runs the control plane of core switching infrastructure, arbitrary code execution on the host operating system can be used to establish persistence on network devices, tamper with routing and switching behavior, or stage lateral movement inside a network fabric.

Root Cause

The root cause is an improper signature verification implementation in the CLI code path [CWE-347]. The verification logic can be satisfied under conditions that do not actually prove the authenticity of the loaded artifact, which allows unsigned or attacker-controlled payloads to be treated as trusted. HPE notes that certain preconditions outside the attacker's control must be met, which limits reliable exploitation but does not eliminate the risk in environments where those conditions naturally occur.

Attack Vector

The attack requires local access to the AOS-CX CLI with administrative credentials. An attacker who has already obtained admin-level access, for example through credential theft, misconfigured TACACS/RADIUS, or a compromised jump host, can invoke the affected CLI functionality to load a crafted artifact. When the environmental preconditions align, the signature check is bypassed and the artifact executes on the underlying operating system. No verified public proof-of-concept exists, and the vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog. The EPSS probability is low, consistent with the local, high-privilege attack profile.

No verified exploit code has been released. See the HPE Security Bulletin for vendor-supplied technical detail.

Detection Methods for CVE-2026-73776

Indicators of Compromise

Administrative CLI sessions that invoke image, firmware, or package loading commands outside of scheduled maintenance windows
Unexpected AOS-CX process activity, new binaries, or configuration drift on the underlying operating system after CLI use
Failed or anomalous signature verification log entries followed by successful load operations on the same artifact

Detection Strategies

Baseline the set of administrators authorized to load software or execute privileged CLI commands on AOS-CX, and alert on deviations
Correlate switch AAA logs, syslog, and change-management records to identify CLI activity that lacks a matching change ticket
Monitor for authentications to AOS-CX from hosts or accounts that do not normally manage network infrastructure

Monitoring Recommendations

Forward AOS-CX syslog and AAA accounting records to a central analytics platform for long-term retention and correlation
Enable command accounting on TACACS+ or RADIUS so every privileged CLI command is captured with the executing identity
Alert on repeated signature verification errors, which can indicate probing for the bypass condition

How to Mitigate CVE-2026-73776

Immediate Actions Required

Apply the fixed AOS-CX firmware version identified in the HPE Security Bulletin as soon as change windows allow
Rotate administrative credentials for AOS-CX devices and audit the list of accounts with write-level privileges
Restrict management-plane access to a dedicated out-of-band network and a small set of jump hosts

Patch Information

HPE has released updated AOS-CX builds that address the signature verification bypass. Administrators should consult the vendor bulletin hpesbnw05134en_us for the mapping of affected trains to fixed versions, then plan upgrades using standard AOS-CX image installation and reboot procedures. Verify image integrity using HPE-published hashes before deployment.

Workarounds

Enforce role-based access control so only a minimal set of accounts hold the administrative privileges required to reach the vulnerable CLI path
Require multi-factor authentication on all administrative access to network infrastructure, including bastion and jump hosts
Disable or tightly restrict any CLI features that load external artifacts if they are not required for operations
Monitor for and investigate any use of software-loading commands until patches are fully deployed