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'BadPower' Attack Can Rig a Fast Charger to Melt Your Devices

On some fast chargers, an attacker can exploit the read and write ability over the USB port to send malicious code to alter the charger’s firmware, according to researchers in China.

 & Michael Kan Principal Reporter

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(Credit: Tencent)

A fast charger is supposed to replenish a phone’s battery in minutes. Just don’t let a hacker mess the firmware, or the charger might cause your devices to catch on fire. 

Security researchers in China were recently able to infect a variety of fast chargers with malicious code to deliver more voltage than the connected device could handle. The overload caused the components inside the affected electronics to spark, sizzle, and melt. 

The findings come from Tencent’s Xuanwu Lab, which noticed a potential problem with the technology. To deliver energy, fast chargers use a USB port, which can hook up to your smartphone via a cable. However, in some cases the same USB port will also operate as a data connection, enabling you to read and write information to the charger’s firmware. 

According to Xuanwu Lab, the data connection on these USB ports have no safeguards in place to prevent tampering. As a result, an attacker can exploit the read and write ability to send malicious code to alter the charger’s firmware. 

By default, the fast charger is supposed to only deliver the standard 5 volts of electricity for devices that don’t support the fast charging standard. However, by rewriting the firmware you can cause the charger to constantly deliver up to 20 volts, which will trigger a dangerous overload. 

The firmware can also be manipulated to lie. For example, the charger can tell a connected smartphone that supports fast charging that it’s delivering 5 volts of power. But in reality, the charger is actually delivering 20 volts, which would likely damage the battery over time.

The lab demonstrated its “BadPower” vulnerability in a video. The malicious code is carried on a smartphone, which transmits the attack once it’s connected to the fast charger. Once the firmware is altered, the fast charger first delivers 5 volts of electricity before quickly ramping up to 20. 

In the video, the lab then connected the fast charger to an electronic product, which began to spark 10 seconds after it was plugged in. 

According to Xuanwu Lab, there are at least 234 fast-charging-related products on the market. It decided to test 35 of them, and found that 18 from eight different brands suffered from the BadPower vulnerability. 

The lab didn’t name the vulnerable products, but it has contacted the affected vendors and China’s National Vulnerability Database about the potential danger. The good news is that vendors can patch the problem with a firmware update, which can be delivered via a connected smartphone. To fix the problem, the lab is recommending manufacturers place protections around the fast charger’s USB data connection, or remove the feature all together. The firmware on board the chargers should also be vetted for vulnerabilities.

Further Reading

Batteries & Power Reviews

About Our Expert

Michael Kan

Michael Kan

Principal Reporter

My Experience

I've been a journalist for over 15 years. I got my start as a schools and cities reporter in Kansas City and joined PCMag in 2017, where I cover satellite internet services, cybersecurity, PC hardware, and more. I'm currently based in San Francisco, but previously spent over five years in China, covering the country's technology sector.

Since 2020, I've covered the launch and explosive growth of SpaceX's Starlink satellite internet service, writing 600+ stories on availability and feature launches, but also the regulatory battles over the expansion of satellite constellations, fights with rival providers like AST SpaceMobile and Amazon, and the effort to expand into satellite-based mobile service. I've combed through FCC filings for the latest news and driven to remote corners of California to test Starlink's cellular service.

I also cover cyber threats, from ransomware gangs to the emergence of AI-based malware. In 2024 and 2025, the FTC forced Avast to pay consumers $16.5 million for secretly harvesting and selling their personal information to third-party clients, as revealed in my joint investigation with Motherboard.

I also cover the PC graphics card market. Pandemic-era shortages led me to camp out in front of a Best Buy to get an RTX 3000. I'm now following how the AI-driven memory shortage is impacting the entire consumer electronics market. I'm always eager to learn more, so please jump in the comments with feedback and send me tips.

The Best Tech I've Had:

  • My first video game console: a Nintendo Famicom
  • I loved my Sega Saturn despite PlayStation's popularity.
  • The iPod Video I received as a gift in college
  • Xbox 360 FTW
  • The Galaxy Nexus was the first smartphone I was proud to own.
  • The PC desktop I built in 2013, which still works to this day.

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