CVE-2026-49199 Overview
CVE-2026-49199 is a command injection vulnerability (CWE-77) affecting the Acer Predator Connect W6x router firmware. Crafted Message Queuing Telemetry Transport (MQTT) messages can trigger command injection, resulting in root-level code execution on the target device. The flaw is network-exploitable, requires no authentication, and requires no user interaction. Successful exploitation grants full administrative control of the router.
Critical Impact
Unauthenticated attackers can execute arbitrary commands as root on affected Acer Predator Connect W6x devices by sending crafted MQTT messages over the network.
Affected Products
- Acer Predator Connect W6x (hardware)
- Acer Predator Connect W6x Firmware
- All firmware versions prior to the vendor-supplied fix referenced in the Acer advisory
Discovery Timeline
- 2026-05-29 - CVE-2026-49199 published to the National Vulnerability Database (NVD)
- 2026-06-04 - Last updated in NVD database
Technical Details for CVE-2026-49199
Vulnerability Analysis
The Acer Predator Connect W6x router exposes an MQTT message handler that processes attacker-controlled input without proper sanitization. The handler passes fields from incoming MQTT messages into a shell context, where embedded shell metacharacters are interpreted rather than treated as literal data. This results in command injection, classified under [CWE-77] (Improper Neutralization of Special Elements used in a Command).
Because the MQTT broker or client process runs with root privileges on the device, any injected command executes with root-level authority. Attackers gain full control of the router operating system, including network configuration, firewall rules, DNS settings, and persistent storage.
The Exploit Prediction Scoring System (EPSS) places this vulnerability at the 77th percentile, indicating elevated likelihood of exploitation attempts relative to typical CVEs.
Root Cause
The firmware fails to validate or neutralize special characters in MQTT payload fields before passing them to a system command interpreter. Shell metacharacters such as semicolons, backticks, pipes, and command substitution sequences are processed as control syntax instead of being escaped or rejected.
Attack Vector
An attacker sends a crafted MQTT message to the router. The payload embeds shell metacharacters within a field that the firmware later concatenates into a shell command. The shell executes the injected portion as a separate command running as root. No credentials or user interaction are required. See the Acer Knowledge Base Article for vendor-supplied technical detail.
No public proof-of-concept exploit is currently available for this vulnerability.
Detection Methods for CVE-2026-49199
Indicators of Compromise
- Unexpected MQTT traffic to or from the router on TCP port 1883 or 8883 from untrusted sources
- Outbound connections from the router to unknown command-and-control hosts
- Unauthorized changes to router configuration, DNS settings, or firewall rules
- New or modified scripts in persistent storage on the device
Detection Strategies
- Inspect MQTT message payloads for shell metacharacters such as ;, |, &, $(), and backticks in fields handled by the router
- Monitor router system logs for unexpected process executions spawned from the MQTT handler
- Use network intrusion detection rules to flag MQTT CONNECT or PUBLISH messages containing command-injection patterns directed at affected devices
Monitoring Recommendations
- Capture and review northbound and southbound traffic to the router management interface
- Alert on outbound connections initiated by the router to non-vendor infrastructure
- Track firmware version inventory across deployed Predator Connect W6x devices to confirm patch status
How to Mitigate CVE-2026-49199
Immediate Actions Required
- Apply the firmware update referenced in the Acer Knowledge Base Article as soon as it is available for your device
- Restrict network reachability of MQTT ports (1883, 8883) on affected routers to trusted hosts only
- Isolate Predator Connect W6x devices from untrusted networks and the public internet where feasible
- Audit router configuration and credentials for signs of unauthorized modification
Patch Information
Acer has published guidance in the vendor knowledge base. Refer to the Acer Knowledge Base Article for the firmware version that remediates CVE-2026-49199 and for installation instructions specific to the Predator Connect W6x.
Workarounds
- Block inbound MQTT traffic at the network perimeter until firmware can be applied
- Disable any router features that expose the MQTT service externally if configuration permits
- Place the router behind an upstream firewall that enforces strict allowlisting for management protocols
# Example perimeter firewall rules to block external MQTT access
iptables -A INPUT -p tcp --dport 1883 -j DROP
iptables -A INPUT -p tcp --dport 8883 -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
