Brave Browser Claims Alibaba's AliExpress Caught Tracking Users With Hidden Audio Fingerprinting

Alibaba-owned online retailer AliExpress was allegedly found running hidden Web Audio processes on its homepage that measured how devices processed a silent sound, a technique used for browser fingerprinting, claimed the Brave browser. The practice came to light after a user noticed interference with Bluetooth headphones. After the incident, privacy-focused browser Brave stated that its protections stop the tracking by default. "Alibaba's AliExpress was caught using users' audio systems to track them," Brave said in a post on X (formerly Twitter).

How the Tracking Works

Fingerprinting allows websites to identify users without cookies by combining device details such as screen size, installed fonts, and other characteristics into a persistent identifier. In this case, AliExpress scripts generated a silent audio signal through the Web Audio API and analysed small variations in how different devices processed it. Those differences stem from variations in CPUs, sound cards, browsers, and related hardware or software. Qwen Beats Meta and Google With 3 Billion Downloads; Alibaba’s Model Becomes No. 1 Open-Source AI.

Alibaba's AliExpress Was Caught Using Users' Audio Systems To Track Them

The scripts, part of Alibaba’s anti-fraud and security tooling, created audio processing graphs that connected to the system audio destination at zero volume. No audible sound played, and conventional media elements were absent, so browser mute controls had no effect. The resulting measurements contributed to a broader device fingerprint that also included canvas rendering, WebGL data, hardware details, and other signals. The data was sent to Alibaba servers.

Fingerprinting Is a Way That Websites Can Identify You Without Cookies, Says Brave

Brave Says It Has Protected Users Against Audio Fingerprinting

We Also Block the Specific Scripts Used by AliExpress for the Tracking Method Mentioned Above

Discovery Through an Unexpected Side Effect

A researcher documented the issue after multipoint Bluetooth headphones failed to switch audio properly from a computer to a phone while an AliExpress tab remained open. Closing the tab restored normal behaviour. Investigation showed the silent audio graphs kept the computer's audio path active, preventing the headphones from switching cleanly. The finding was detailed in a blog post published around August 20 and later discussed on technical forums.

Brave's Protections

Brave said it has protected users against audio fingerprinting and other forms of fingerprinting for more than six years by default. The browser injects random data into certain outputs so that different sites see different fingerprints, which also reset across sessions. It additionally blocks the specific scripts associated with the AliExpress method. No user settings changes are required for these protections. Brave noted that trackers continue to develop new fingerprinting techniques and said it recently added defences against GPU fingerprinting that limit identification via graphics cards or drivers. Apple Develops Custom AI Model for China With Alibaba Support Ahead of Apple Intelligence Launch.

Context and Broader Implications

Large e-commerce platforms often use device fingerprinting for fraud detection, bot prevention, and risk scoring, as cookies can be cleared or altered. Audio fingerprinting relies on measurable differences in how identical signals are rendered across systems and is typically combined with other signals for greater effectiveness. Privacy researchers and browser makers have long viewed such techniques as invasive because they can enable persistent tracking with limited user visibility or control.

Users of other browsers can block the identified scripts with content blockers such as uBlock Origin, though this may affect site functionality in some cases. The episode highlights ongoing tensions between anti-abuse measures and user privacy on the web.

(The above story first appeared on LatestLY on Aug 23, 2026 09:19 AM IST. For more news and updates on politics, world, sports, entertainment and lifestyle, log on to our website latestly.com).