CVE-2026-50227

Executive Summary

CVE-2026-50227 is an unauthenticated local command-injection vulnerability in Acer NitroSense (versions up to and including 5.2.62). An attacker who can reach the application's localhost WebSocket endpoint can connect to an embedded MQTT broker without authentication and invoke exposed ddsc RPC functions — including child_process.execSync() — resulting in arbitrary command execution in the context of the NitroSense application. Because the broker binds to a local WebSocket endpoint and requires no credentials, any local user or process (including sandboxed code, a malicious browser page reaching localhost, or a low-privilege foothold) can escalate to code execution within the application's security context.

Technical Analysis

The vulnerability class is OS command injection (CWE-78) exposed through an improperly authenticated local message bus. Acer NitroSense ships an internal MQTT broker reachable over a localhost WebSocket endpoint. That broker exposes a set of "ddsc" RPC functions to any client that connects; there is no authentication gate described, and an attacker is not required to hold any prior privilege beyond network reachability to the local WebSocket listener.

The critical exposure is that the ddsc RPC surface includes a wrapper around Node.js child_process.execSync(). execSync() runs a command line through a system shell and returns the buffered output. When an RPC method forwards attacker-controlled data into that call without sanitization or before any authorization check, the attacker controls the shell command that is executed. The vulnerability therefore has two chained weaknesses: (1) missing authentication/authorization on the broker endpoint, and (2) unsafe construction of a shell command from RPC input.

Key characteristics from the available data:

• Authentication: none required ("unauthenticated local attacker").
• Attack surface: MQTT broker over the application's localhost WebSocket endpoint.
• Reachable methods: "exposed ddsc RPC functions," with child_process.execSync() named explicitly.
• Execution context: the application context (NitroSense), not necessarily SYSTEM/root — final privilege depends on how the software runs.

The exploit does not require user interaction from the victim. Reconnaissance and triggering are driven entirely by the attacker's ability to initiate a WebSocket connection to the loopback interface. Because the broker is a general-purpose pub/sub transport, a message published to the topic that maps to the vulnerable RPC method is sufficient to reach the sink; no GUI navigation, file drop, or macro is required.

No public proof-of-concept, exploit code, or Nuclei template exists at the time of writing, and the CVSS score and vector are not yet assigned by NVD; the vector shown above is an analyst-derived baseline consistent with the described impact (local, low complexity, no privileges, no user interaction, high confidentiality/integrity/availability).

Exploitation Scenarios

The following chain is inferred strictly from the NVD description; no implementation-specific names beyond those stated are assumed.

1. Reconnaissance / target identification. The attacker is already executing locally on a host running Acer NitroSense <= 5.2.62 — for example as a low-privilege user, a malicious process, or code executing in a sandbox. The attacker enumerates local listening sockets to identify the NitroSense MQTT broker's localhost WebSocket endpoint. No credentials are needed because the endpoint is unauthenticated.

2. Connection to the broker. The attacker opens a WebSocket client connection to the local endpoint and performs a standard MQTT handshake. Since no authentication is enforced, the broker accepts the session and grants access to the published/subscribed topic space.

3. Invocation of exposed ddsc RPC functions. The attacker publishes a message to the topic that routes to the vulnerable ddsc RPC method. The RPC handler passes the attacker-supplied value into child_process.execSync(). Because the value is not sanitized before shell execution, the attacker appends their own command using standard shell metacharacters, causing arbitrary command execution in the application's context.

4. Post-exploitation impact. Commands run with the privileges of the NitroSense process. Depending on how the service is installed, this can range from the interactive user's rights up to SYSTEM/root. Practical outcomes include data theft, persistence (e.g., scheduled tasks or startup entries), disabling security tooling, lateral movement using the host's credentials, and — because NitroSense is a gaming/performance utility often run with elevated rights — likely local privilege escalation from a low-privilege starting point.

No public PoC is available; the attack chain is inferred from the vulnerability class and the described exposed RPC method. Any browser or script capable of initiating a loopback WebSocket connection is a plausible delivery vehicle for the second stage.

Impact Assessment

Impact is high across confidentiality, integrity, and availability once the local broker is reachable: arbitrary command execution yields read/write control over host data and the ability to disrupt or ransom the endpoint. The primary blast radius is individual gaming/consumer endpoints running Acer NitroSense, but the same software is common on Acer Nitro laptops used by developers and IT staff, making the desktops a pivot point into corporate networks. CVSS subscores: Attack Vector Local (requires local reachability), Attack Complexity Low, Privileges Required None, User Interaction None, Scope Unchanged, Confidentiality/Integrity/Availability High. The absence of a CVSS assignment and of any CISA KEV listing reflects the current low observed exploitation, not low severity. There is no public PoC and no active campaign is known, so the immediate internet-wide threat is limited; the risk is concentrated in multi-user or shared-workstation environments and in bring-your-own-device fleets where a low-privilege user or malicious local code can reach the loopback broker. Unpatched status (0/4 patch confidence) means every deployment at or below 5.2.62 remains exposed until the vendor issues a fix or mitigations are applied.

Detection Guidance

Sigma Rule

title: Acer NitroSense MQTT Broker Local RPC Command Execution
id: 6d1a9f42-3b7e-4c5a-9f10-2b7c8e4d1a55
status: experimental
description: Detects a process spawned by Acer NitroSense (or the Node.js runtime hosting it) executing a shell, consistent with abuse of child_process.execSync() via the unauthenticated localhost MQTT broker (CVE-2026-50227).
references:
  - https://nvd.nist.gov/vuln/detail/CVE-2026-50227
author: valtersit.com
date: 2026-01-01
tags:
  - attack.execution
  - attack.t1059
  - attack.t1203
logsource:
  category: process_creation
  product: windows
detection:
  selection_parent:
    ParentImage|endswith:
      - '\NitroSense.exe'
      - '\NitroSenseService.exe'
  selection_child:
    Image|endswith:
      - '\cmd.exe'
      - '\powershell.exe'
      - '\pwsh.exe'
      - '\wscript.exe'
      - '\cscript.exe'
      - '\curl.exe'
      - '\certutil.exe'
  condition: selection_parent and selection_child
falsepositives:
  - Legitimate NitroSense update or telemetry helpers invoking a shell (validate before alerting)
level: high

YARA Rule

rule CVE_2026_50227_NitroSense_RPC_ExecSync_Indicator
{
    meta:
        author = "valtersit.com"
        description = "Detects strings associated with the Acer NitroSense MQTT/WebSocket ddsc RPC surface and execSync command sink (CVE-2026-50227)"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2026-50227"
        date = "2026-01-01"

    strings:
        $a = "execSync" ascii nocase
        $b = "ddsc" ascii nocase
        $c = "mqtt" ascii nocase
        $d = "ws://" ascii nocase
        $e = "child_process" ascii nocase

    condition:
        uint16(0) == 0x5A4D or uint32(0) == 0x464C457F
        and 2 of ($a, $b, $c, $d, $e)
}

Suricata IDS Rule

alert tcp $HOME_NET any -> 127.0.0.1 any (msg:"CVE-2026-50227 Acer NitroSense MQTT WebSocket RPC Command Injection Attempt"; flow:to_server,established; content:"|81|"; depth:1; content:"GET"; http_method; content:"Upgrade"; http_header; nocase; content:"websocket"; http_header; nocase; pcre:"/(execSync|ddsc)/i"; classtype:attempted-admin; sid:202650227; rev:1; metadata:created_at 2026_01_01, updated_at 2026_01_01;)

Elastic Detection

process where event.type == "start" and
process.parent.name in ("NitroSense.exe", "NitroSenseService.exe", "node.exe") and
process.name in ("cmd.exe", "powershell.exe", "pwsh.exe", "wscript.exe", "cscript.exe", "curl.exe") and
process.args : ("*execSync*", "*ddsc*", "*cmd /c*")

Splunk SPL Query

index=endpoint sourcetype="XmlWinEventLog:Microsoft-Windows-Sysmon/Operational" EventCode=1
| search (ParentImage="*\\NitroSense.exe" OR ParentImage="*\\NitroSenseService.exe")
  AND (Image="*\\cmd.exe" OR Image="*\\powershell.exe" OR Image="*\\pwsh.exe" OR Image="*\\wscript.exe" OR Image="*\\cscript.exe" OR Image="*\\curl.exe")
| stats count min(_time) as first_seen max(_time) as last_seen values(CommandLine) as command_lines by ComputerName, User, ParentImage, Image
| where count > 0

Wazuh OSSEC Rule

<group name="windows,sysmon,acer_nitrosense,">
  <rule id="100227" level="12">
    <if_sid>61603</if_sid>
    <field name="win.eventdata.parentImage">NitroSense</field>
    <field name="win.eventdata.image">\\cmd\.exe|\\powershell\.exe|\\pwsh\.exe|\\wscript\.exe|\\cscript\.exe</field>
    <description>CVE-2026-50227: shell process spawned by Acer NitroSense (possible MQTT RPC command injection)</description>
    <mitre>
      <id>T1059</id>
      <id>T1203</id>
    </mitre>
  </rule>
</group>

Mitigation & Patch Guidance

Patch confidence: 0/4 (UNPATCHED — no patch evidence from any tracked source).

1. Immediate mitigations (no vendor fix available).

   • Restrict access to the localhost WebSocket/MQTT endpoint. Where possible, firewall loopback traffic on the broker's listening port for other local users/processes, and remove the software from multi-user or shared machines until a fix exists.
   • Close or block the WebSocket listener using host firewall rules and application-level allowlisting (bind-to-loopback-only is already assumed — the risk is same-host clients, so process isolation and OS-level access control matter).
   • Run NitroSense with least privilege (do not install/run it elevated or as a service) so an exploited command executes with minimal rights.
   • Apply EDR/allowlisting to prevent NitroSense and its Node.js runtime from spawning shells or interpreters.
   • Monitor the supplied detection rules for shell processes parented by the NitroSense binary.

2. Patch / upgrade steps.

   • No patch is currently identified. Monitor Acer's official support/download page and security advisories for NitroSense and install the first fixed build above 5.2.62 when released.
   • Track the vendor's CVE publication and re-evaluate Patch Confidence once a fixed version is confirmed. Until then, treat all versions <= 5.2.62 as vulnerable.

3. Long-term hardening.

   • Require authentication and authorization on any embedded local broker or RPC service; default-deny unauthenticated localhost clients.
   • Never pass client-controlled data into child_process.execSync(); use argument-array APIs and validate/allowlist inputs.
   • Enforce application sandboxing and least-privilege service accounts for OEM utilities.
   • Maintain an SBOM of OEM/bloatware components and re-scan against NVD/OSV feeds as advisories are published.

References

• NVD — CVE-2026-50227: https://nvd.nist.gov/vuln/detail/CVE-2026-50227
• MITRE CWE-78 (Improper Neutralization of Special Elements used in an OS Command): https://cwe.mitre.org/data/definitions/78.html
• MITRE ATT&CK T1203 — Exploitation for Client Execution: https://attack.mitre.org/techniques/T1203/
• MITRE ATT&CK T1059 — Command and Scripting Interpreter: https://attack.mitre.org/techniques/T1059/
• OWASP — OS Command Injection: https://owasp.org/www-community/attacks/Command_Injection
• CISA Known Exploited Vulnerabilities Catalog (CVE-2026-50227 not listed as of report date): https://www.cisa.gov/known-exploited-vulnerabilities-catalog

No vendor advisory, threat actor campaign, or exploit-in-the-wild evidence is available at the time of writing. EPSS has not yet scored this CVE.