CVE-2026-73751

Executive Summary

CVE-2026-73751 is an OS command injection vulnerability (CWE-77) in HPE ArubaOS-CX affecting the web-based management interface. An attacker who holds only low-privileged, authenticated access can submit crafted input through that interface to execute arbitrary commands on the underlying operating system, yielding full compromise of the switch/controller host. With a CVSS base score of 8.8 and High impact across Confidentiality, Integrity, and Availability, this represents a serious post-authentication privilege-escalation and lateral-movement risk for any ArubaOS-CX deployment exposing its web UI to a network segment reachable by non-administrative users.

Technical Analysis

The vulnerability is classified as CWE-77, Improper Neutralization of Special Elements used in a Command ("Command Injection"). Per the NVD description, the flaw resides in the web-based management interface of HPE ArubaOS-CX and is reachable by a user holding authenticated but low-privileged access. The essential mechanism is that user-supplied input passed through the web management interface is used to construct an operating-system command without adequate neutralization of command separators or interpreter metacharacters, allowing an attacker to break out of the intended command context and append or substitute arbitrary commands.

Two properties drive the severity:

1. Authentication is required but weakly gated. The CVSS vector PR:L (Privileges Required: Low) confirms an attacker needs a valid account, but not administrative rights. This means any read-only operator, guest, or similarly constrained account becomes a viable launch point for full OS-level compromise — a classic privilege-escalation path.
2. No user interaction. UI:N means the malicious payload is delivered purely server-side once the crafted input is submitted; no victim needs to click anything.
3. Full impact triad. C:H/I:H/A:H indicates complete loss of confidentiality, integrity, and availability on the affected host. Because the injected commands run on the underlying network operating system, the attacker is not confined to the web application's context.

The attack surface is the web-based management interface — the HTTP/HTTPS administrative plane of ArubaOS-CX (commonly exposed on the switch's management address). Note that the supplied intelligence does not disclose the specific parameter, endpoint, or command handler involved; accordingly, no function names, API paths, or parameter identifiers are asserted here, and insufficient technical detail is available to reconstruct the exact code path. The exploitable behavior should be understood at the vulnerability-class level: unneutralized input reaching an OS command execution sink.

ArubaOS-CX is a network operating system deployed on HPE Aruba campus and data-center switching platforms. Compromise of the OS layer of a network device is materially worse than compromise of an ordinary application server, because the device sits on the control plane of the network fabric.

Exploitation Scenarios

No public proof-of-concept, Nuclei template, or exploit code was identified in the supplied data, and CISA KEV does not list this CVE. The attack chain below is therefore inferred from the vulnerability class (CWE-77 command injection) and the CVSS vector, not from observed exploit artifacts.

1. Reconnaissance / target identification. The attacker enumerates reachable ArubaOS-CX management interfaces — typically via Shodan-style fingerprinting (http.title:"ArubaOS-CX") or internal network scanning of management VLANs and OOB management segments. The objective is to locate the web management UI and confirm the version is in the vulnerable set (version set is not specified in the available data).
2. Credential acquisition / access. Because PR:L is required, the attacker must already possess low-privileged credentials. Realistic vectors include default or weak operator accounts, previously harvested credentials from phishing or password reuse, a low-privilege account issued to a contractor or monitoring integration, or credentials obtained through a separate vulnerability. The flaw does not bypass authentication on its own.
3. Triggering the flaw class. Once authenticated with the low-privileged account, the attacker submits crafted input through a web management interface function that wraps user input into an OS command. At the class level, the payload injects shell metacharacters (command separators, substitution syntax, or pipeline operators) so that the input is interpreted as additional commands by the underlying shell rather than as inert data. The precise sink parameter is not disclosed in the provided intelligence and is not fabricated here.
4. Payload execution and post-exploitation impact. The injected commands execute with the privileges of the web management service on the ArubaOS-CX underlying OS. Achieving arbitrary command execution on a network switch's OS enables: reading and modifying device configuration and secrets (AAA credentials, SNMP communities, PSKs, certificates) for total confidentiality loss; altering routing/switching behavior, ACLs, and spanning/mirroring configuration for total integrity loss; and disabling services, crashing the management plane, or wiping configuration for total availability loss. From there, the device becomes a pivot into the network fabric — traffic interception, lateral movement to other managed devices, and persistent configuration backdoors are all within reach.

Because the flaw is post-authentication, the primary detection opportunity is not at the perimeter but in the behavior of authenticated low-privileged sessions.

Impact Assessment

CVSS 3.1 base score 8.8 (High) with subscores:

• Attack Vector: Network (AV:N) — exploitable remotely over the network; no physical or adjacent access required.
• Attack Complexity: Low (AC:L) — no special conditions or race windows; exploitation is repeatable.
• Privileges Required: Low (PR:L) — any low-privileged authenticated account suffices; this is the key amplifier.
• User Interaction: None (UI:N) — no victim action needed.
• Scope: Unchanged (S:U) — impact is scored within the same security authority, though in practice OS-level root on a switch has network-wide blast radius beyond the scored scope.
• Confidentiality/Integrity/Availability: High/High/High — complete loss on the affected device.

Business impact: ArubaOS-CX devices are core network infrastructure. A compromised switch or controller grants the attacker a vantage point at the heart of the environment — the ability to intercept, redirect, or deny traffic; to harvest credentials transiting the fabric; and to use the device as a trusted internal foothold that bypasses perimeter defenses. For regulated environments, full compromise of network infrastructure typically triggers material incident-response obligations.

Blast radius: every ArubaOS-CX instance with the vulnerable web management interface exposed to any network segment reachable by a low-privileged account. Devices with management interfaces reachable from user VLANs, wireless guest networks, or unsegmented flat networks carry the highest practical risk.

EPSS is 0.00376 (31.3rd percentile) — low near-term exploitation likelihood by mass-scanning campaigns, consistent with the post-authentication precondition and absence of public exploit code. This should not be read as low risk: targeted actors with existing low-privileged access or credential sets are exactly the population that this flaw empowers, and EPSS measures broad exploitation probability, not targeted risk.

Detection Guidance

Sigma Rule

title: Potential ArubaOS-CX Web Management Command Injection (CVE-2026-73751)
id: 7b1c4e92-3a8d-4f21-9c6e-0d5a2f8b1e77
status: experimental
description: Detects shell metacharacter payloads submitted to the ArubaOS-CX web management interface by authenticated low-privileged users, indicative of CWE-77 command injection as described in CVE-2026-73751.
references:
  - https://nvd.nist.gov/vuln/detail/CVE-2026-73751
author: valtersit.com Threat Intelligence
date: 2026/01/01
logsource:
  category: webserver
  product: aruba
  service: http
detection:
  selection_method:
    cs-method:
      - POST
      - GET
  selection_uri:
    cs-uri-stem|contains:
      - '/rest/'
      - '/api/'
      - '/cgi-bin/'
  selection_metachars:
    cs-uri-query|contains:
      - ';'
      - '|'
      - '`'
      - '$('
      - '&&'
      - '||'
      - '>'
      - '../'
  selection_body_metachars:
    cs-uri-query|contains:
      - '%3B'
      - '%7C'
      - '%60'
      - '%24%28'
  condition: selection_method and selection_uri and (selection_metachars or selection_body_metachars)
falsepositives:
  - Legitimate administrative scripts that pass semicolons or pipe characters in values
  - Monitoring integrations generating encoded query strings
level: high
tags:
  - attack.t1190
  - attack.t1059.004
  - cve.2026-73751

YARA Rule

rule CVE_2026_73751_ArubaOS_CX_CmdInjection
{
    meta:
        description = "Detects shell metacharacter injection payloads targeting ArubaOS-CX web management interface (CVE-2026-73751, CWE-77)"
        author = "valtersit.com Threat Intelligence"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2026-73751"
        date = "2026-01-01"
        severity = "high"

    strings:
        $aruba = "ArubaOS-CX" ascii nocase
        $swarm = "aruba" ascii nocase

        $p1 = ";" ascii
        $p2 = "|" ascii
        $p3 = "$(" ascii
        $p4 = "`" ascii
        $p5 = "&&" ascii
        $p6 = "||" ascii

        $cmd1 = "wget " ascii nocase
        $cmd2 = "curl " ascii nocase
        $cmd3 = "/bin/sh" ascii nocase
        $cmd4 = "chmod " ascii nocase
        $cmd5 = "nc -e" ascii nocase
        $cmd6 = "base64 -d" ascii nocase

        $enc1 = "%3B" ascii nocase
        $enc2 = "%7C" ascii nocase
        $enc3 = "%60" ascii nocase

    condition:
        filesize < 1MB and
        (
            ($aruba and any of ($p*) ) or
            (any of ($p*) and any of ($cmd*)) or
            (any of ($enc*) and any of ($cmd*))
        )
}

Suricata IDS Rule

alert http any any -> any any (msg:"CVE-2026-73751 Attempted ArubaOS-CX Web Management Command Injection"; flow:established,to_server; http.method; content:"POST"; http.uri; content:"/rest/"; nocase; http.request_body; content:"|3B|"; http.request_body; content:"|7C|"; http.request_body; pcre:"/(\;|\||\&\&|\|\||\$\(|\`)/R"; reference:cve,2026-73751; reference:url,nvd.nist.gov/vuln/detail/CVE-2026-73751; classtype:web-application-attack; sid:202673751; rev:1; metadata:created_at 2026_01_01, updated_at 2026_01_01, attack_target Web_Server, deployment Perimeter, confidence High;)

alert http any any -> any any (msg:"CVE-2026-73751 ArubaOS-CX Encoded Metacharacter Injection"; flow:established,to_server; http.uri; content:"Aruba"; nocase; http.request_body; content:"%3B"; nocase; http.request_body; content:"%7C"; nocase; reference:cve,2026-73751; classtype:web-application-attack; sid:202673752; rev:1; metadata:created_at 2026_01_01, updated_at 2026_01_01;)

Elastic Detection

sequence by host.name with maxspan=5s
  [ network where network.direction == "inbound" and
      http.request.method in ("POST", "GET") and
      process.name : "aruba*" ]
  [ process where event.type == "start" and
      process.parent.name : ("httpd", "nginx", "webserver", "lighttpd", "aruba*") and
      process.name : ("sh", "bash", "busybox", "ash", "wget", "curl", "nc", "chmod", "base64") ]

Splunk SPL Query

index=network_sourcetype=aruba* OR sourcetype=access_combined sourcetype IN ("aruba:cx", "aruba:cx:audit", "aruba:cx:httpd")
| eval raw=coalesce(cs_uri_query, cs_uri_stem, _raw)
| eval suspicious=if(match(raw, "(?i)(%3[bB]|%7[cC]|%60|%24%28|;|\||&&|\|\||\$\()")
      AND match(raw, "(?i)(wget|curl|/bin/sh|chmod|nc -e|base64)"), 1, 0)
| where suspicious=1 OR (match(raw, "(?i)(%3[bB]|%7[cC]|%60)") AND match(uri_path, "(?i)(/rest/|/api/|/cgi-bin/)"))
| stats count min(_time) as first_seen max(_time) as last_seen values(src_ip) as src_ips values(user) as users by host uri_path
| convert ctime(first_seen) ctime(last_seen)
| sort - count

Wazuh OSSEC Rule

<group name="aruba,web,arubaos_cx,cve-2026-73751,">
  <rule id="202673751" level="12">
    <if_sid>31100</if_sid>
    <decoded_as>web-accesslog</decoded_as>
    <url>(\;|\||\&\&|\|\||\$\(|\`|%3[bB]|%7[cC]|%60|%24%28)</url>
    <description>CVE-2026-73751: ArubaOS-CX web management interface received shell metacharacters in request - possible command injection (CWE-77)</description>
    <mitre>
      <id>T1190</id>
      <id>T1059.004</id>
    </mitre>
    <group>web_attack,command_injection,</group>
  </rule>

  <rule id="202673752" level="13">
    <if_sid>202673751</if_sid>
    <match>wget |curl |/bin/sh|chmod |nc -e|base64 -d</match>
    <description>CVE-2026-73751: ArubaOS-CX web request contains shell metacharacters AND execution command indicators - high confidence exploitation attempt</description>
    <group>web_attack,command_injection,</group>
  </rule>

  <rule id="202673753" level="14">
    <if_sid>80784</if_sid>
    <match>aruba</match>
    <description>CVE-2026-73751: ArubaOS-CX management daemon spawned a shell or process-execution binary - possible OS command injection impact</description>
    <group>arubaos_cx,os_command_execution,</group>
  </rule>
</group>

Detection note: these rules are behavior-class detections for CWE-77 command injection against an ArubaOS-CX web management interface. They intentionally key on metacharacter and interpreter-command patterns rather than on any specific parameter name, because no parameter-level detail is available for this CVE. Tune the URI path lists to match the actual default management endpoints in your deployment.

Mitigation & Patch Guidance

Patch confidence: 2/4 — CLAIMED. A single source (NVD) claims a patch is available, but no vendor advisory URL, fixed version number, or patch identifier was supplied. Operators must independently verify the fixed release through HPE's official Aruba security advisory channel before relying on it.

1. Immediate mitigations (do before patching is confirmed):

   • Segment the ArubaOS-CX web management interface. Place it on a dedicated out-of-band management VLAN, never reachable from user, guest, wireless-client, or general corporate segments. This single control neutralizes the network-reachable (AV:N) exploitation path for the vast majority of attackers.
   • Restrict access with management ACLs so only hardened jump hosts/administration subnets can reach the web UI ports.
   • Audit and minimize low-privileged accounts. Since PR:L is the foothold requirement, eliminate shared, contractor, monitoring, and default operator accounts whose compromise grants the precondition. Enforce MFA at the administrative gateway where supported.
   • Disable or restrict the web-based management interface entirely if device management can be performed exclusively via SSH/CLI for your environment.
   • Increase logging/auditing on authenticated web management sessions and alert on the detection signatures above.
   • Where supported, enable configuration integrity monitoring / config-change alerting so unauthorized post-exploitation changes are visible quickly.

2. Patch/upgrade steps:

   • Check HPE Aruba Networking's security advisory portal for the ArubaOS-CX advisory corresponding to CVE-2026-73751. The advisory is the authoritative source for affected version lists and the fixed release — neither is available in the supplied data.
   • Note that the supplied data provides an empty affected-versions list; do not assume any version is safe or unsafe without consulting the vendor advisory.
   • Stage the vendor firmware upgrade in a lab, validate against your routing/switching and wireless configuration, then roll in maintenance windows with rollback plans.
   • After upgrade, rotate credentials and secrets on the device (AAA, SNMP, local accounts, certificates) as a precaution in case prior low-privileged account compromise enabled pre-patch exploitation.

3. Long-term hardening:

   • Enforce privileged-access management: unique named accounts, least privilege, MFA, and session recording for all network device administration.
   • Adopt a strict management-plane security architecture — all network device management in a dedicated OOB segment, inaccessible from data/voice/wireless planes.
   • Maintain continuous firmware hygiene: subscribe to HPE Aruba security advisories and treat switch OS patching with the same cadence as server/endpoint patching.
   • Deploy configuration-drift and command-audit telemetry from network devices into the SIEM, with alerting on shell-process spawning and unexpected config changes.
   • Periodically review low-privileged network device accounts and integrations (NMS, monitoring, automation) as attack surface, since they satisfy PR:L.

References

1. NVD entry for CVE-2026-73751 — https://nvd.nist.gov/vuln/detail/CVE-2026-73751 (primary source for the description, CVSS vector, CWE-77 classification, and the claimed patch indication; contains no affected-version list, no PoC, and no vendor advisory URL).
2. HPE Aruba Networking Security Advisories — https://www.arubanetworks.com/support-services/security-bulletins/ (authoritative source to confirm the fixed ArubaOS-CX release and affected version matrix; not enumerated in the supplied data).
3. CWE-77: Improper Neutralization of Special Elements used in a Command ('Command Injection') — https://cwe.mitre.org/data/definitions/77.html (defines the vulnerability class and the general neutralization failure mechanism).
4. MITRE ATT&CK T1190: Exploit Public-Facing Application — https://attack.mitre.org/techniques/T1190/ (tactic mapping for the web-interface attack surface).
5. CISA Known Exploited Vulnerabilities Catalog — https://www.cisa.gov/known-exploited-vulnerabilities-catalog (CVE-2026-73751 is NOT listed, as of the supplied data; no exploit-in-the-wild evidence, no public PoC, no Nuclei template, and no known threat actor campaign has been identified for this CVE).

Note on absence of adversary intelligence: No public exploit code, no Nuclei template, and no KEV listing are associated with this CVE. There is consequently no observable exploitation telemetry or attributed threat-actor activity to report. EPSS 0.00376 (31.3rd percentile) indicates low predicted mass-exploitation probability, consistent with the low-privileged-authentication precondition and the current absence of a weaponized public exploit.