CVE-2026-10871 in Tomato
Summary
by MITRE • 06/05/2026
A vulnerability has been found in Shibby Tomato 1.28.0000. This vulnerability affects the function start_6rd_tunnel of the file /sbin/rc of the component Web UI. Such manipulation of the argument ipv6_6rd_borderrelay leads to os command injection. It is possible to launch the attack remotely. The exploit has been disclosed to the public and may be used. This project is superseded by FreshTomato.
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Analysis
by VulDB Data Team • 06/05/2026
The vulnerability in Shibby Tomato 1.28.0000 represents a critical command injection flaw within the web user interface component that affects the start_6rd_tunnel function in the /sbin/rc file. This issue stems from inadequate input validation and sanitization of the ipv6_6rd_borderrelay argument, creating a pathway for malicious actors to execute arbitrary operating system commands. The vulnerability exists within the router firmware's network configuration handling mechanism, specifically targeting the 6rd tunnel setup functionality that enables ipv6 connectivity through ipv4 networks. The flaw allows attackers to manipulate the command execution flow by injecting malicious input into the border relay parameter, effectively bypassing normal security controls and gaining unauthorized access to the underlying operating system.
The technical exploitation of this vulnerability leverages the fundamental weakness in input handling where user-supplied data flows directly into system command execution without proper sanitization or validation. This creates a classic os command injection scenario that aligns with CWE-77 and CWE-88 categories, where external input is incorporated into command strings without proper escaping or filtering. The vulnerability's remote attack surface is particularly concerning as it allows adversaries to trigger the command injection from outside the local network, making it accessible to anyone who can reach the router's web interface. The attack vector requires no authentication for the initial exploitation phase, as the vulnerability exists in the web management interface that typically requires legitimate credentials for access but can be exploited through the command injection flaw itself.
The operational impact of this vulnerability extends beyond simple unauthorized command execution, as it provides attackers with full control over the router's operating system and potentially the entire network segment it manages. An attacker could leverage this vulnerability to establish persistent access, modify network configurations, redirect traffic, or even use the compromised device as a pivot point for attacking other systems within the network. The vulnerability's presence in the 6rd tunnel functionality means that attackers could manipulate ipv6 routing configurations, potentially enabling them to bypass network security controls or create unauthorized communication channels. This risk is amplified by the fact that the exploit has been publicly disclosed, removing any barrier to exploitation and making it immediately available to threat actors.
Mitigation strategies for this vulnerability must address both the immediate exposure and the underlying architectural issues that enabled the command injection. The most effective immediate solution involves upgrading to FreshTomato or another supported firmware version that has addressed this vulnerability through proper input validation and sanitization of user parameters. System administrators should implement network segmentation and access controls to limit exposure, while also ensuring that the web interface is not directly accessible from untrusted networks. Additional protective measures include disabling unnecessary services, implementing proper firewall rules, and monitoring network traffic for suspicious activity that might indicate exploitation attempts. The vulnerability also highlights the importance of maintaining up-to-date firmware and following security best practices such as the principle of least privilege, where only necessary services are enabled and access is restricted to authorized personnel. Organizations should also consider implementing intrusion detection systems and regular security assessments to identify similar vulnerabilities in other network infrastructure components. This vulnerability demonstrates the critical importance of secure coding practices and input validation in embedded systems, particularly those with web interfaces that handle user-supplied data.