The Micca Auto Electronics Co., Ltd. KE700 car alarm system suffers from a critical vulnerability identified as CVE-2026-2540, categorized under CWE-288 (Authentication Bypass Using an Alternate Path or Channel) and CWE-294 (Authentication Bypass). The root cause is flawed resynchronization logic in the rolling code mechanism used to secure remote keyless entry. Rolling codes are designed to prevent replay attacks by changing the code with each use; however, the KE700 system's logic can be manipulated by replaying two previously captured codes in a specific sequence. This sequence forces the system to accept stale rolling codes, effectively bypassing authentication and allowing an attacker to clone the alarm key. The cloned key can then be used to lock or unlock the vehicle without authorization. The attack requires no privileges or user interaction and can be performed remotely with low attack complexity, though it requires prior capture of valid codes. The vulnerability impacts the confidentiality and integrity of vehicle access controls, potentially leading to unauthorized physical access or theft. The CVSS 4.0 vector (AV:A/AC:L/AT:N/PR:N/UI:N/VC:L/VI:H/VA:N/SC:L/SI:L/SA:H/V:D/RE:M) indicates an attack vector requiring adjacent network access, low attack complexity, no privileges or user interaction, low confidentiality impact, high integrity impact, no availability impact, low scope change, low security requirements, high safety impact, and moderate remediation effort. No patches or exploits in the wild are currently reported, but the vulnerability remains a significant risk until addressed.

For European organizations and individuals, this vulnerability poses a tangible risk of vehicle theft or unauthorized access, especially for those using vehicles equipped with the Micca KE700 alarm system. The ability to clone keys and bypass authentication undermines physical security controls, potentially leading to loss of assets, increased insurance claims, and reputational damage for fleet operators or car rental services. Critical infrastructure entities relying on vehicles with this system could face operational disruptions if vehicles are compromised. Additionally, the breach of vehicle security can facilitate further criminal activities such as cargo theft or unauthorized transport. The vulnerability’s exploitation does not require user interaction or privileges, increasing the likelihood of successful attacks in environments where attackers can capture rolling codes, such as parking lots or public areas. The moderate remediation effort and lack of available patches mean that affected users must rely on interim security measures, increasing operational overhead and risk exposure.

Given the absence of available patches, European organizations should implement layered security controls to mitigate risk. These include: 1) Physically securing vehicles in monitored or restricted areas to reduce the chance of code capture; 2) Using Faraday pouches or signal-blocking key fobs to prevent unauthorized code interception; 3) Monitoring vehicle access logs and installing additional alarm or immobilizer systems independent of the KE700 system; 4) Educating users on the risks of leaving key fobs unattended or near vehicle entry points; 5) Engaging with Micca Auto Electronics for firmware updates or security advisories and applying patches promptly once available; 6) For fleet operators, implementing vehicle tracking and rapid response protocols to detect and respond to unauthorized access; 7) Considering replacement of vulnerable alarm systems with more secure alternatives if feasible. These measures go beyond generic advice by focusing on physical security enhancements and operational controls tailored to the nature of this vulnerability.