CVE-2026-2540 in Car Alarm System
Summary
by MITRE • 02/15/2026
The Micca KE700 system contains flawed resynchronization logic and is vulnerable to replay attacks. This attack requires sending two previously captured codes in a specific sequence. As a result, the system can be forced to accept previously used (stale) rolling codes and execute a command. Successful exploitation allows an attacker to clone the alarm key. This grants the attacker unauthorized access to the vehicle to unlock or lock the doors.
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Analysis
by VulDB Data Team • 02/19/2026
The Micca KE700 system represents a critical security vulnerability that undermines the integrity of vehicle access control mechanisms through flawed resynchronization logic. This vulnerability operates within the realm of rolling code systems that are designed to prevent replay attacks by ensuring each code sequence is unique and time-bound. The system's failure to properly validate code sequences creates an exploitable condition where attackers can manipulate the authentication process through carefully orchestrated code reuse. The vulnerability specifically targets the cryptographic protocols that govern how rolling codes are generated, transmitted, and validated, creating a window of opportunity for malicious actors to bypass legitimate authentication procedures. The attack vector requires precise timing and sequence manipulation to exploit the resynchronization flaw, making it particularly dangerous as it can be executed without requiring sophisticated technical knowledge beyond understanding the specific code patterns.
The technical flaw manifests in the system's inability to properly detect and reject stale rolling codes that have already been used in previous authentication attempts. This weakness creates a scenario where the system accepts previously captured code sequences as valid, effectively breaking the fundamental principle that rolling codes should only be valid for a single use or within a very limited time window. The vulnerability operates at the protocol level where the system fails to maintain proper state tracking of code sequences, allowing attackers to replay codes in a specific temporal sequence that the system interprets as legitimate. This flaw aligns with common weaknesses described in CWE-310 and CWE-327, which address cryptographic implementation errors and weak cryptographic algorithms that fail to provide adequate security guarantees. The system's resynchronization logic appears to lack proper validation mechanisms that would normally detect code reuse patterns and reject them as invalid.
The operational impact of this vulnerability extends far beyond simple unauthorized access to vehicle doors, as it provides attackers with the capability to clone legitimate alarm key fobs through the replay attack mechanism. This cloning capability represents a complete compromise of the vehicle's physical security model, allowing attackers to gain persistent access to the vehicle's systems without requiring physical possession of the legitimate key fob. The ability to unlock and lock vehicle doors remotely through this method creates significant risk for vehicle theft and unauthorized vehicle operation. The vulnerability affects automotive security systems that rely on rolling code technology, which is widely deployed in modern vehicles and represents a fundamental security weakness that can be exploited by attackers with minimal resources. This type of attack falls under the ATT&CK framework category of privilege escalation and lateral movement, as it allows attackers to gain unauthorized access to vehicle systems that should remain protected from external interference.
Mitigation strategies for this vulnerability require immediate implementation of enhanced code validation mechanisms that properly track and reject previously used rolling codes. System administrators and vehicle manufacturers should implement robust state management protocols that maintain proper records of code sequences and their usage status. The solution involves strengthening the resynchronization logic to include comprehensive validation checks that prevent code reuse within acceptable time windows. Security patches should address the underlying cryptographic implementation flaws by ensuring proper code sequence validation and implementing time-based code expiration mechanisms. Organizations should also consider implementing additional security layers such as challenge-response protocols that require dynamic verification of code authenticity. The mitigation approach should align with industry standards for automotive cybersecurity and may require updates to the system's firmware to address the specific resynchronization logic flaws that enable this attack vector. Regular security assessments and code sequence monitoring should be implemented to prevent similar vulnerabilities from emerging in future system implementations.