CVE-2026-10065: Shibby Tomato Buffer Overflow Vulnerability

CVE-2026-10065 Overview

CVE-2026-10065 is a stack-based buffer overflow vulnerability in Shibby Tomato 1.28, an unsupported router firmware distribution. The flaw resides in the get_ups_field function within tomatodata.cgi. Attackers can exploit the issue remotely by manipulating the Date argument passed to the CGI handler. The weakness is categorized under [CWE-119]: Improper Restriction of Operations within the Bounds of a Memory Buffer. Shibby Tomato has been superseded by FreshTomato, and the affected firmware no longer receives maintenance updates.

Critical Impact
Authenticated remote attackers can trigger memory corruption in tomatodata.cgi to compromise router confidentiality, integrity, and availability on an end-of-life firmware platform.

Affected Products

Shibby Tomato firmware version 1.28
The tomatodata.cgi web interface component
Project status: superseded by FreshTomato and no longer supported by the maintainer

Discovery Timeline

2026-05-29 - CVE-2026-10065 published to the National Vulnerability Database (NVD)
2026-05-29 - Last updated in NVD database

Technical Details for CVE-2026-10065

Vulnerability Analysis

The vulnerability exists in the get_ups_field function inside tomatodata.cgi, a CGI handler shipped with Shibby Tomato 1.28. The function processes the Date argument from HTTP request input without enforcing proper bounds on the destination buffer. When an attacker submits an oversized Date value, the function writes past the allocated stack buffer. This corrupts adjacent stack memory, including saved return addresses and local variables.

Because the firmware runs on consumer-grade router hardware with minimal exploit mitigations, successful exploitation can lead to control-flow hijacking or service crashes. The vulnerability falls under [CWE-119] for memory bounds violations. Detailed technical analysis is available in the Gitee CVE Issue Discussion and VulDB Vulnerability Details.

Root Cause

The root cause is missing input length validation on the Date parameter before it is copied into a fixed-size stack buffer in get_ups_field. The function relies on unsafe string handling without enforcing destination buffer limits. This pattern is common in legacy embedded web interfaces that prioritize footprint over defensive coding.

Attack Vector

The attack vector is network-based and requires low-privilege authentication to the router management interface. An attacker sends a crafted HTTP request to tomatodata.cgi containing an overlong Date parameter. No user interaction is required. The vulnerability mechanism is described in prose because no verified public exploit code is available. Refer to the VulDB CTI Data for Vulnerability for additional context.

Detection Methods for CVE-2026-10065

Indicators of Compromise

HTTP requests to tomatodata.cgi containing unusually long Date parameter values
Unexpected httpd or CGI process crashes recorded in router system logs
Unscheduled reboots of routers running Shibby Tomato 1.28
Outbound connections from the router to unfamiliar hosts following administrative access

Detection Strategies

Inspect web server access logs on the router for malformed or oversized query strings targeting tomatodata.cgi
Deploy network intrusion detection signatures that flag HTTP requests with excessively long Date arguments to CGI endpoints
Correlate authentication events on the router management interface with subsequent CGI errors

Monitoring Recommendations

Forward router syslog data to a centralized log platform and alert on repeated CGI process termination events
Monitor management interface access for unexpected source IP addresses, particularly from the internet
Track configuration changes on Tomato-based devices that occur outside scheduled maintenance windows

How to Mitigate CVE-2026-10065

Immediate Actions Required

Migrate affected devices from Shibby Tomato 1.28 to the actively maintained FreshTomato firmware
Restrict access to the router management interface to trusted internal networks only
Disable remote WAN-side administration on all Tomato-based routers
Rotate router administrator credentials and enforce strong, unique passwords

Patch Information

No vendor patch is available. Shibby Tomato is no longer supported by the maintainer, and the project has been superseded by FreshTomato. Users should replace the firmware with a supported distribution or retire the affected hardware. See the VulDB Submission Confirmation for additional vendor status information.

Workarounds

Place affected routers behind a network segment that blocks untrusted access to the management interface
Apply firewall rules to drop inbound HTTP/HTTPS traffic to the router from the WAN interface
Limit administrative accounts on the router and audit existing user sessions

bash

# Example iptables rules to restrict management interface access to a trusted subnet
iptables -A INPUT -i br0 -s 192.168.1.0/24 -p tcp --dport 80 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -i vlan2 -p tcp --dport 80 -j DROP