The U.S. Cybersecurity and Infrastructure Security Agency (CISA) has published an Industrial Control Systems (ICS) advisory detailing a critical vulnerability in Yadea's T5 electric bicycle. Tracked as CVE-2025-70994, the flaw allows an attacker within wireless range of the e-bike to forge key-fob signals and gain unauthorized control. This marks one of the first high-profile security warnings targeting electric bicycles, highlighting how connected mobility devices are increasingly becoming attack surfaces.

What is CVE-2025-70994?

CVE-2025-70994 is a security vulnerability in the wireless authentication mechanism of the Yadea T5 e-bike. The flaw resides in how the bike's receiver validates signals from its key fob. An unauthenticated attacker can exploit this by capturing and replaying valid key-fob transmissions, or by injecting forged signals that mimic a legitimate fob. The attack requires only physical proximity—typically within 30 to 50 meters—to the target e-bike. No authentication credentials or prior access are needed.

According to CISA's advisory, the vulnerability has a CVSS v3.1 base score of 8.1, placing it in the "high severity" category. The attack vector is classified as "adjacent network," meaning the attacker must be within radio range. However, the low complexity and lack of required privileges make exploitation relatively straightforward.

Impact on Yadea T5 Owners

For owners of the Yadea T5, the practical implications are serious. An attacker could unlock the bike, start the motor, and ride away without the owner's key fob. Since the attack is local and wireless, it can be carried out discreetly in parking lots, bike racks, or any public area. The forged signal can also potentially disable the bike's anti-theft alarm, making theft even easier.

Yadea is one of the world's largest electric scooter and e-bike manufacturers, with the T5 model being popular for its long range and utility features. The vulnerability undermines the trust that users place in the bike's security systems, especially for those who rely on it as a primary mode of transportation.

Technical Details of the Flaw

CISA's advisory does not disclose full exploit code but provides enough technical context to understand the root cause. The Yadea T5 uses a proprietary wireless protocol for key-fob communication, likely operating in the 315 MHz or 433 MHz ISM band. The vulnerability stems from inadequate cryptographic protections—specifically, the absence of rolling code or challenge-response mechanisms. This means that the key-fob signal is static or predictable, allowing an attacker to capture a single transmission and replay it indefinitely.

In more secure systems, rolling codes change with each use, preventing replay attacks. The Yadea T5's implementation apparently lacks this, making it susceptible to simple replay attacks. Additionally, the advisory mentions that the receiver does not verify the integrity or authenticity of the signal beyond a basic identifier. This opens the door for attackers to brute-force or spoof the ID.

Mitigation and Response

CISA recommends that Yadea T5 owners take several steps to mitigate the risk:
- Keep the e-bike's firmware updated. Yadea has not yet released a patch, but owners should monitor for updates.
- Use additional physical locks, such as U-locks or chain locks, to supplement the electronic security.
- Park the bike in secure, well-lit areas where attackers cannot easily approach within wireless range.
- Disable wireless features if possible, though this may not be an option on the T5.

Yadea has been contacted by CISA but has not publicly commented on a fix timeline. The advisory notes that Yadea is aware of the vulnerability and is working on a firmware update. However, until a patch is deployed, users remain at risk.

Broader Implications for E-Bike Security

The Yadea T5 vulnerability is a wake-up call for the entire e-bike industry. As e-bikes become more connected—with GPS tracking, smartphone apps, and keyless entry—they also inherit the security challenges of IoT devices. Many manufacturers prioritize convenience and cost over robust security, leading to vulnerabilities like CVE-2025-70994.

This advisory from CISA is significant because it treats an e-bike as an ICS component. While that classification may seem surprising, modern e-bikes contain embedded controllers, wireless modules, and battery management systems that fit the ICS definition. CISA's involvement signals that e-bike vulnerabilities are now being treated with the same seriousness as those in industrial control systems.

Comparison with Other Vehicle Vulnerabilities

Keyless entry vulnerabilities are not new in the automotive world. Researchers have demonstrated relay attacks against cars from Toyota, Tesla, and BMW. However, e-bikes have largely flown under the radar. The Yadea T5 flaw is simpler to exploit than many car key attacks, which often require expensive relay equipment. A simple software-defined radio (SDR) costing less than $50 can capture and replay the Yadea T5 signal.

What Users Should Do Now

If you own a Yadea T5, the immediate action is to not rely solely on the key-fob security. Use a high-quality U-lock to secure the frame to a fixed object. Consider adding a GPS tracker that can alert you to unauthorized movement. Also, check Yadea's official website and social media channels for firmware updates. In the meantime, avoid parking the bike in areas where attackers can easily approach unnoticed.

Conclusion

CVE-2025-70994 is a stark reminder that security must keep pace with innovation. The Yadea T5 is a capable and popular e-bike, but its wireless authentication flaw leaves it vulnerable to theft. While a firmware fix is expected, the timeline is unclear. Until then, owners must take physical security measures seriously. This incident should also encourage regulators and manufacturers to establish minimum security standards for connected e-bikes, just as they have for other vehicles.