(NewsNation) — Cybersecurity researchers say they’ve discovered a supermassive leak of data being dubbed the “mother of all breaches.”

The 26 billion records are from “thousands of meticulously compiled and reindexed leaks, breaches, and privately sold databases,” Cybernews reported. The news outlet discovered the exposed records in conjunction with Bob Dyachenko, cybersecurity researcher at SecurityDiscovery.com.

The dataset isn’t an entirely new batch of records, but rather a compilation of mostly information from past data breaches. Cybernews reported the files could contain new data that wasn’t published before, though.

“The dataset is extremely dangerous as threat actors could leverage the aggregated data for a wide range of attacks, including identity theft, sophisticated phishing schemes, targeted cyberattacks, and unauthorized access to personal and sensitive accounts,” researchers told Cybernews.

No group has claimed responsibility for the breach.

McAfee, a company that develops computer antivirus software, suggested in a blog post that people take steps to protect their information and said “given the scale of the breach, your best bet is to act like your data was caught up in it.”

The company recommends changing passwords, using two-factor authentication and using identity monitoring and theft protection services.

The largest number of records in the breach, 1.5 billion, came from Tencent, a Chinese messaging app, according to Cybernews. More than 500 million were from Weibo, another Chinese messaging app.

Hundreds of millions of records also came from MySpace (360 million), Twitter (281 million) and LinkedIn (251 million).