CVE-2026-73754

Executive Summary

CVE-2026-73754 is a denial-of-service (DoS) vulnerability affecting the command line interface (CLI) of AOS-CX, the network operating system powering Aruba Networks (HPE) switching platforms. An authenticated attacker with low-privilege CLI access can trigger a condition that disrupts the normal operation of the vulnerable system, potentially causing service interruptions, device instability, or complete unavailability of management interfaces. The vulnerability carries a CVSS score of 5.3 (Medium) with high availability impact, and no patch has been released by the vendor at the time of writing.

Technical Analysis

The NVD description identifies the vulnerability class as a denial-of-service condition residing in the command line interface of AOS-CX. The key characteristics derived from the description are as follows:

Vulnerability Class: Denial-of-service in command-line interface processing. The flaw mechanism involves improper handling of specific CLI commands or input sequences that, when executed by an authenticated user, cause the system to enter an abnormal state. This is characteristic of CWE-755 (Improper Handling of Exceptional Conditions), where the CLI parser or command execution engine fails to gracefully handle unexpected or edge-case input, resulting in process crash, resource exhaustion, or system hang.

Attack Surface: The attack surface is the AOS-CX command line interface. Access to the CLI requires authentication, meaning the attacker must possess valid credentials — the CVSS vector confirms this with PR:L (low privileges required). The CLI may be accessible via SSH, console, or telnet, depending on the network device configuration. The CVSS vector also indicates AV:N (network attack vector), confirming that the CLI is network-reachable.

Authentication Requirement: The vulnerability requires an authenticated session. The CVSS component PR:L indicates that the attacker needs only low-level privileges — typically a read-only or basic user account in the AOS-CX privilege hierarchy — rather than administrator-level access. This significantly expands the population of potential attackers, as many network operators provision low-privilege accounts for monitoring or auditing purposes.

Complexity Considerations: The attack complexity is rated high (AC:H). This suggests that successful exploitation requires specific conditions — perhaps particular CLI command combinations, timing windows, or environmental factors. An attacker may need to execute commands in a specific sequence, or race conditions may be involved in triggering the vulnerable code path.

Impact: The availability impact is rated high (A:H), meaning successful exploitation can result in complete or near-complete loss of availability of the affected system. No confidentiality or integrity impact is present. For a network switch running AOS-CX, this could manifest as CLI unresponsiveness, management plane failure, data plane disruption in extreme cases, or the need for a manual device reboot.

Patch Status: No patch evidence exists from any tracked source (patch confidence: 0/4). The vendor has not released a fix, no affected version list has been published, and no workarounds have been documented.

Exploitation Scenarios

Attack Chain — Inferred from Vulnerability Class:

1. Reconnaissance/Target Identification: The attacker identifies AOS-CX devices exposed on the network. This may be performed via network scanning for management ports (SSH typically on TCP/22, telnet on TCP/23) and banner grabbing to confirm the operating system. Shodan queries such as product:"HPE Aruba Networking" or banner searches for AOS-CX signatures could assist in identifying vulnerable devices. Device identification is further aided by the fact that network switches often reveal their operating system in SSH banners.

2. Authentication: The attacker must obtain valid credentials. This could be through credential stuffing, password spraying using default credentials (if not changed by the administrator), phishing of network operations staff, or harvesting leaked credentials from other breaches. The low privilege requirement (PR:L) is critical — a basic monitoring account with CLI access is sufficient. An attacker does not need administrative credentials to trigger this vulnerability.

3. Triggering the Flaw: Once authenticated, the attacker interacts with the CLI and issues commands designed to trigger the denial-of-service condition. The vulnerability class (CWE-755) indicates the flaw is likely triggered by commands that cause the CLI parser or command processor to encounter an exceptional condition it cannot handle. This could involve command injection via specially formatted input, malformed command syntax edge cases, commands that cause excessive resource consumption, or command sequences that place the device into a state from which it cannot recover. The specific command syntax is not disclosed in the available data.

4. Post-Exploitation Impact: Successful triggering results in denial of service. The attacker can repeat the exploitation to keep the device unavailable or the service temporarily disrupted until the device recovers or is manually rebooted. This is a persistence mechanism for disruption — the attacker can repeatedly trigger the vulnerability to maintain device unavailability. For a network switch operating in a production environment, this could result in:

   • Loss of switch management capabilities
   • Potential network disruption if the switch is handling critical traffic
   • Operational overhead as network administrators scramble to restore service

Because no public PoC exists for this vulnerability, the attack chain is inferred from the vulnerability class and CVSS characteristics. The high attack complexity (AC:H) suggests reliable exploitation may require research into the specific CLI parsing flaws or favorable timing conditions.

Impact Assessment

Technical Impact: The vulnerability enables a low-privilege authenticated user to cause a high-severity denial-of-service condition on the target AOS-CX device. The CVSS availability sub-score (A:H) indicates severe impact on system availability — likely rendering the CLI unresponsive and potentially impacting the switch's forwarding plane if the CLI crash affects the overall system process. The requirement for authentication and high attack complexity reduces the overall severity to Medium (5.3).

Business Impact: AOS-CX powers Aruba's CX series data center and campus switching products. These devices are commonly deployed in enterprise networks, data centers, and campus environments. An attacker exploiting this vulnerability could:

• Disrupt network management and monitoring capabilities
• Potentially interrupt network operations if the device becomes non-functional
• Force manual intervention, requiring physical or out-of-band access to recover the device
• Create extended downtime windows while recovery is coordinated

Blast Radius: The attack is device-scoped (S:U indicates the scope is unchanged). The direct impact is confined to the individual switch. However, in a network architecture where a single switch provides aggregation or core services, the downstream impact could affect all devices connected through it. The attack requires valid credentials — organizations with exposed management interfaces, weak authentication policies, or compromised credentials are at elevated risk.

Operational Impact: Since no patch exists, affected organizations must rely on compensating controls. The high complexity requirement may limit immediate exploitation likelihood, but the vulnerability remains viable for targeted attacks by actors who already possess low-privilege access.

Detection Guidance

Sigma Rule

title: AOS-CX CLI Denial-of-Service Exploitation Attempt
id: 9e6f8c9a-3d2b-4e5f-8a1b-6c7d8e9f0a1b
status: experimental
description: Detects CLI commands on AOS-CX devices that may trigger CVE-2026-73754 denial-of-service vulnerability
references:
    - https://nvd.nist.gov/vuln/detail/CVE-2026-73754
author: Valtersit Threat Intelligence
date: 2026/01/15
logsource:
    category: application
    product: hpe_aoscx
    service: cli
detection:
    selection_crash_commands:
        - Command: 
            - '*debug*'
            - '*crash*'
            - '*restart*'
    selection_repetitive:
        - Command: 'terminal length 0\nterminal length 0'
    selection_unusual_sequences:
        - Command: '*|*'
        - Command: '*;*'
    condition: selection_crash_commands or selection_repetitive or selection_unusual_sequences
level: high
tags:
    - attack.t1499
    - cve.2026.73754
falsepositives:
    - Legitimate administrative debugging activity requires review

YARA Rule

rule AOSCX_CLI_DOS_Exploit_Patterns
{
    meta:
        author = "Valtersit Threat Intelligence"
        description = "Detects log patterns and command sequences associated with AOS-CX CLI DoS exploitation attempts"
        cve = "CVE-2026-73754"
        date = "2026-01-15"
        severity = "medium"
    strings:
        $aoscx_banner = "AOS-CX" nocase
        $cli_error_1 = "command not found" nocase
        $cli_error_2 = "invalid input" nocase
        $cli_error_3 = "error" nocase
        $memory_error = "out of memory" nocase
        $crash_indicator = "core dump" nocase
        $syslog_restart = "restart" nocase
        $repeat_command = "terminal length 0" nocase
        $debug_enable = "debug" nocase ascii
        $pipeline_char = "|" ascii
        $semicolon_char = ";" ascii
    condition:
        $aoscx_banner and
        (
            (2 of ($cli_error_*) and $memory_error) or
            ($crash_indicator and $syslog_restart) or
            ($repeat_command and $debug_enable) or
            ($pipeline_char and $semicolon_char)
        )
}

Suricata IDS Rule

alert tcp any any -> any 22 (msg:"AOS-CX CLI DoS Exploitation Attempt - CVE-2026-73754"; flow:established,to_server; content:"AOS-CX"; nocase; offset:50; depth:200; content:"debug "; nocase; sid:20267375401; rev:1; classtype:attempted-dos; reference:cve,2026-73754; metadata:attack_target network_device, created_at 2026_01_15, deployment perimeter, signature_severity Major, tag cve202673754, threat_name AOSCX_CLI_DOS_Exploit)

alert tcp any any -> any 23 (msg:"AOS-CX CLI DoS Exploitation Attempt via Telnet - CVE-2026-73754"; flow:established,to_server; content:"AOS-CX"; nocase; offset:50; depth:200; content:"debug "; nocase; sid:20267375402; rev:1; classtype:attempted-dos; reference:cve,2026-73754; metadata:attack_target network_device, created_at 2026_01_15, deployment perimeter, signature_severity Major, tag cve202673754, threat_name AOSCX_CLI_DOS_Exploit_Telnet)

Elastic Detection

sequence by host.name with maxspan=30s
  [ authentication where process.name : "sshd" and event.action : "authentication_success" and user.name : "*" ]
  [ process where process.name : "*cli*" and (
        process.command_line : "*debug*" or
        process.command_line : "*restart*" or
        process.command_line : "*reload*" or
        process.command_line : "*crash*"
    ) ]
  [ process where process.name : "*aoscx*" and event.action : "killed" ]

Splunk SPL Query

index=nids OR index=syslog sourcetype=aruba:aoscx OR index=authentication 
  (User=* AND (Command="*debug*" OR Command="*restart*" OR Command="*reload*" OR Command="*crash*")) 
  OR (sourcetype=ssh AND message="AOS-CX" AND message="*debug*") 
  OR (sourcetype=syslog AND message="*AOS-CX*" AND (message="*core dump*" OR message="*panic*" OR message="*restart*")) 
  | stats count min(_time) as first_seen max(_time) as last_seen by src_ip, dest_ip, User, Command 
  | where count >= 3 
  | table first_seen, last_seen, src_ip, dest_ip, User, Command, count

Wazuh OSSEC Rule

<group name="aoscx,">

  <rule id="100735" level="12">
    <if_sid>100000</if_sid>
    <match>debug</match>
    <match>AOS-CX</match>
    <description>AOS-CX CLI debug command triggered - potential DoS exploitation (CVE-2026-73754)</description>
    <group>access_denied,</group>
    <mitre>
      <id>T1499</id>
    </mitre>
  </rule>

  <rule id="100736" level="12">
    <if_sid>100000</if_sid>
    <match>core dump</match>
    <match>AOS-CX</match>
    <description>AOS-CX core dump detected - potential DoS exploitation (CVE-2026-73754)</description>
    <group>attacks,</group>
    <mitre>
      <id>T1499</id>
    </mitre>
  </rule>

  <rule id="100737" level="10">
    <if_sid>100000</if_sid>
    <match>restart</match>
    <match>AOS-CX</match>
    <description>AOS-CX device restart after repeated CLI commands - potential DoS exploitation (CVE-2026-73754)</description>
    <group>attacks,</group>
    <mitre>
      <id>T1499</id>
    </mitre>
  </rule>

</group>

Mitigation & Patch Guidance

Critical Note: At the time of writing, no patch exists for CVE-2026-73754. Patch confidence is rated 0/4 — no patch evidence has been identified from any tracked source. The vendor has not released a fix, and no affected version list has been published.

Immediate Mitigations:

1. Restrict CLI Access: Limit SSH access to management interfaces through network access control lists (ACLs). Only allow administrative workstations and jump hosts to reach the management plane of AOS-CX devices. This reduces the attack surface to authorized network segments.
2. Enforce Strong Authentication: Implement multi-factor authentication (MFA) for network device access where supported. Ensure all local accounts use strong, unique passwords. Disable default credentials immediately.
3. Minimize Low-Privilege Accounts: Review and audit all accounts with CLI access. Disable any accounts that are not actively used. For monitoring accounts, restrict them to read-only privileges if the platform supports granular privilege levels.
4. Monitor CLI Activity: Implement real-time monitoring of CLI sessions, logging all commands executed on AOS-CX devices. Alert on unusual command sequences or repeated failed attempts.
5. Isolate Management Plane: Use out-of-band management networks (OOB) or dedicated management VLANs with strict access policies. Disable telnet in favor of SSH.

Patch/Upgrade Steps:

1. Subscribe to Aruba/HPE security advisories and monitor the HPE Aruba Networking Security Bulletin portal for announcements related to CVE-2026-73754.
2. When a patch becomes available, test it in a non-production environment first, then schedule upgrade windows for all affected devices.
3. Reference the vendor advisory for specific patch version numbers and upgrade prerequisites.

Long-Term Hardening:

1. Reduce Privilege Surface: Where possible, avoid creating shared accounts. Use individual accounts with role-based access control to minimize the number of users who can reach the CLI.
2. Session Timeouts: Configure aggressive idle session timeouts on network device CLI to reduce the window for session hijacking or orphaned sessions.
3. Configuration Backups: Maintain current configuration backups for all network devices to enable rapid recovery in the event of exploitation.
4. Regular Security Reviews: Conduct periodic audits of device configurations, user accounts, and access controls. Verify that management interfaces are not exposed to untrusted networks.
5. Deploy Compensating Controls: Use network-based intrusion detection/prevention systems to monitor for anomalous CLI traffic patterns targeting network devices.

References

1. NVD Entry: https://nvd.nist.gov/vuln/detail/CVE-2026-73754 — Official NIST National Vulnerability Database entry containing the CVE description.

2. HPE Aruba Networking Security Advisories: https://www.arubanetworks.com/support-services/security-bulletins/ — Vendor security bulletin portal where the advisory for CVE-2026-73754 will be published upon patch availability.

3. CWE-755 Reference: https://cwe.mitre.org/data/definitions/755.html — MITRE Common Weakness Enumeration entry describing improper handling of exceptional conditions, the vulnerability class relevant to this CVE.

4. MITRE ATT&CK T1499: https://attack.mitre.org/techniques/T1499/ — MITRE ATT&CK technique documentation for Endpoint Denial of Service, the relevant adversary tactic for this vulnerability.

Threat Actor Activity: No known threat actor campaigns or exploit-in-the-wild evidence have been reported for CVE-2026-73754. The vulnerability is not listed in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public PoC or weaponized exploit code has been identified. Given the medium severity and unpatched status, this vulnerability is primarily of concern for targeted attacks by actors with existing network device access, rather than broad opportunistic exploitation.