CVE-2026-50043: SkyBridge MB-A100/A110 RCE Vulnerability

CVE-2026-50043 Overview

CVE-2026-50043 is an OS command injection vulnerability affecting Seiko Solutions SkyBridge MB-A100 and MB-A110 industrial routers. The flaw stems from improper neutralization of special elements used in operating system commands [CWE-78]. An authenticated attacker with administrative privileges can execute arbitrary OS commands on the underlying system. The issue is documented in JVN Security Advisory and the Seiko Solutions Archive Entry.

Critical Impact
Successful exploitation grants arbitrary OS command execution on the router, enabling attackers to fully compromise confidentiality, integrity, and availability of the device.

Affected Products

SkyBridge MB-A100
SkyBridge MB-A110
Refer to the vendor advisory for exact firmware version ranges

Discovery Timeline

2026-07-01 - CVE-2026-50043 published to NVD
2026-07-01 - Last updated in NVD database

Technical Details for CVE-2026-50043

Vulnerability Analysis

CVE-2026-50043 is classified as OS Command Injection under [CWE-78]. The SkyBridge MB-A100 and MB-A110 devices are industrial LTE/mobile routers used to connect remote equipment to enterprise networks. The vulnerable code path accepts user-supplied input and passes it to an OS-level command interpreter without adequate sanitization. An attacker who has authenticated to the administrative interface can inject shell metacharacters into a vulnerable parameter and execute arbitrary commands with the privileges of the web management process.

Because the SkyBridge devices sit at network edges, code execution on the router allows lateral movement into the internal network, interception of traffic, or persistent implantation of malicious firmware.

Root Cause

The root cause is missing or insufficient neutralization of shell metacharacters in parameters accepted by administrative endpoints. Input data is concatenated into command strings evaluated by a system shell rather than being passed through parameterized APIs or strictly validated against an allowlist.

Attack Vector

Exploitation requires network access to the management interface and valid administrative credentials. The attack complexity is low once authentication is obtained. An attacker submits a crafted request to an administrative endpoint containing shell metacharacters such as ;, |, or backticks appended to legitimate parameter values. The device shell interprets the injected payload and runs it with the privileges of the management service. The EPSS score is 1.129% at the 62.4 percentile.

No verified public proof-of-concept code is available. The vulnerability mechanism is described in prose based on the JVN advisory.

Detection Methods for CVE-2026-50043

Indicators of Compromise

Unexpected outbound connections originating from SkyBridge MB-A100 or MB-A110 management IP addresses
Administrative login events followed by anomalous configuration changes or firmware modifications
HTTP or HTTPS requests to administrative endpoints containing shell metacharacters such as ;, &&, |, or $()

Detection Strategies

Inspect web server and management interface logs for parameter values containing command separators or subshell syntax
Correlate administrative authentication events with subsequent unusual process activity or network flows from the device
Deploy network intrusion detection signatures that flag shell metacharacter patterns in HTTP request bodies targeting SkyBridge management URLs

Monitoring Recommendations

Forward SkyBridge syslog output to a centralized log platform and alert on administrative interface access from unexpected source addresses
Baseline normal management traffic volumes and alert on deviations that may indicate scripted exploitation attempts
Monitor for new or unauthorized administrative accounts created on affected devices

How to Mitigate CVE-2026-50043

Immediate Actions Required

Apply the vendor firmware update for SkyBridge MB-A100 and MB-A110 as referenced in the Seiko Solutions Archive Entry
Restrict access to the administrative interface to trusted management networks only, using firewall rules or VLAN segmentation
Rotate administrative credentials and audit accounts for unauthorized additions

Patch Information

Seiko Solutions has published advisory information for SkyBridge MB-A100 and MB-A110. Consult the JVN Security Advisory and the vendor page for the fixed firmware version and upgrade procedure applicable to your device model.

Workarounds

Disable remote administrative access from untrusted networks until the firmware update is applied
Enforce strong, unique administrative passwords and multi-factor authentication where supported to reduce the risk of credential compromise
Place SkyBridge devices behind a dedicated management network accessible only via jump hosts

bash

# Example ACL restricting SkyBridge management interface to a trusted subnet
# Replace 192.0.2.0/24 with your management network
iptables -A INPUT -p tcp --dport 443 -s 192.0.2.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP