CVE-2026-15544 in Tomato
Summary
by MITRE • 07/13/2026
A vulnerability was determined in Shibby Tomato up to 1.28.0000. Affected is the function getupsvar of the file www/apcupsd/tomatodata.cgi of the component apcupsd. This manipulation of the argument Field causes stack-based buffer overflow. The attack may be initiated remotely. The exploit has been publicly disclosed and may be utilized. This project is superseded by FreshTomato.
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Analysis
by VulDB Data Team • 07/13/2026
The vulnerability identified in Shibby Tomato version 1.28.0000 represents a critical stack-based buffer overflow flaw within the apcupsd component, specifically affecting the getupsvar function in the www/apcupsd/tomatodata.cgi file. This issue arises from insufficient input validation when processing the Field argument, creating an exploitable condition that can be leveraged by remote attackers to execute arbitrary code on affected devices. The vulnerability demonstrates a classic software security weakness where user-controllable input exceeds the bounds of a fixed-length buffer allocated on the stack, potentially leading to memory corruption and system compromise.
The technical exploitation of this buffer overflow vulnerability follows established attack patterns documented in the attack technique framework, specifically aligning with techniques involving stack smashing and code execution via crafted input parameters. The flaw exists within the apcupsd daemon functionality which manages uninterruptible power supply systems, making it particularly concerning as it affects network-accessible services that monitor power status and system health. According to CWE classification, this vulnerability maps directly to CWE-121 Stack-based Buffer Overflow, which describes a condition where data written to a stack buffer exceeds the buffer's capacity, overwriting adjacent memory locations including return addresses and control information.
The operational impact of this vulnerability extends beyond simple code execution capabilities as it provides attackers with potential persistence mechanisms and privilege escalation paths within affected network environments. Remote exploitation means that attackers can initiate attacks from outside the local network without requiring physical access to devices running the vulnerable firmware, making it particularly dangerous for IoT and home networking equipment. The disclosure of public exploits increases the likelihood of real-world attacks against unpatched systems, especially given that this firmware variant is widely deployed in consumer-grade routers and network appliances.
Security practitioners should prioritize immediate mitigation measures including firmware updates to FreshTomato or other supported versions that have addressed this vulnerability, network segmentation to limit access to affected devices, and monitoring for suspicious network traffic patterns. The transition from Shibby Tomato to FreshTomato represents a necessary migration path as the former project has been superseded, indicating that ongoing security support and maintenance are no longer provided for vulnerable versions. Organizations should implement comprehensive patch management procedures and consider network-based intrusion detection systems to identify potential exploitation attempts targeting this specific vulnerability class.
Additional defensive measures include implementing input validation controls at multiple layers of the application architecture, using modern compiler security features such as stack canaries and address space layout randomization, and conducting regular security assessments of embedded firmware components. The vulnerability highlights the importance of maintaining up-to-date firmware versions and demonstrates how legacy software support gaps can create persistent security risks that may remain unaddressed for extended periods. Network administrators should also consider disabling unnecessary services and implementing access controls to minimize the attack surface available to potential exploiters targeting these vulnerable devices.