Data has become one of the most valuable—and most vulnerable—commodities in our hyperconnected digital age. The methods used by cybercriminals, who are always changing their strategies to take advantage of vulnerabilities in even the most secure systems, also progress with technology. Every year, data breaches expose billions of user records, seriously harming both people and businesses. Financial loss, identity theft, reputational damage, and occasionally national security issues are the results of these breaches. The top ten data breaches in history are examined in this article, which has been updated for 2025 to reflect the most recent worldwide events that rocked the tech and cybersecurity industries.

10 Most Impactful Data Breaches Ever

1. Yahoo

Three billion records were lost. Yahoo has a record for the biggest data breach in history, with an astounding 3 billion user accounts stolen. Although the vulnerability was first discovered in 2016, it wasn’t until a year later that its entire extent was made public. Names, email addresses, security questions and answers, and hashed passwords were among the user data that the attackers were able to obtain. Yahoo’s outdated security setup and slow reaction to the discovery exacerbated the vulnerability. The consequences were serious in the long run: Yahoo’s price fell by $350 million when Verizon bought it, and the incident became a case study of how not to manage a breach of this kind.

2. Aadhaar (1.1 billion records in India, 2018)

More than 1.1 billion Indians were impacted by the 2018 hack of the country’s Aadhaar system, one of the biggest biometric databases in the world. Names, addresses, phone numbers, emails, fingerprints, and iris scans were among the information that was made public. The sensitivity of the data involved and the ease of access made this breach especially concerning; according to reports, login keys to the Aadhaar database were sold on WhatsApp for as low as ₹500. Particularly in underdeveloped nations, the incident sparked grave worries about data governance, privacy regulations, and the centralized management of biometric IDs.

3. Facebook has 533 million users (as of 2021)

533 million Facebook users’ personal information was freely shared on a hacker forum in 2021. This incident was caused by web scraping, an automated technique of gathering data from public profiles utilizing a now-fixed vulnerability in Facebook’s contact importer, as opposed to a traditional breach involving internal compromise. Phone numbers, complete names, dates of birth, and location information were among the disclosed data. Although Facebook maintained that this was not a “breach,” there were significant ramifications for privacy and targeted phishing attempts. This incident was a clear reminder that large-scale malicious use of publicly accessible data is still possible.

4. Marriott International: 500 Million Visitors (2018)

The fact that Marriott International’s hack was multi-year, beginning in 2014 and remaining undetected until 2018 made it more harmful. The reservation system of Starwood Hotels, which Marriott purchased in 2016, was compromised by hackers. Up to 500 million guests’ personal information, including addresses, passport numbers, travel information, and in certain situations, encrypted credit card information, was made public by the hack. Ultimately, it was determined that a Chinese cyber-espionage outfit was responsible for the hack, maybe in search of travel intelligence. Due to the event, Marriott’s data management methods came under international investigation, and the company was hit with hefty fines under the GDPR and other privacy laws.

5. LinkedIn (700 million users 2021)

A significant breach involving the collection and online sale of 700 million members’ data occurred on LinkedIn later in 2021. Names, phone numbers, email addresses, and employment information were all included in the dataset, which at the time comprised over 90% of LinkedIn’s member base. Even while LinkedIn maintained that no system had been compromised and no credentials had been disclosed, the extent of the vulnerability made it risky, particularly for phishing and social engineering schemes. Discussions over the morality of data scraping and whether platforms require more robust anti-bot safeguards and limitations on public data were sparked by this hack.

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6. T-Mobile 76 million user

One of the most well-known telecom hacks in recent memory occurred in 2021 when T-Mobile disclosed that 76 million people’s private data, including that of past, present, and even potential customers, had been compromised by a hacker. The attacker took advantage of lax internal safeguards and entered through vulnerable routers. Social Security numbers (SSNs), driver’s license numbers, names, and birth dates were among the information made public. Numerous lawsuits, a $500 million settlement, and a serious damage to T-Mobile’s reputation resulted from the hack. It made clear how urgently robust access control and ongoing infrastructure monitoring are needed in cloud and telecommunications systems.

7. Equifax:147 Million American

One of the biggest credit reporting companies in the US, Equifax, experienced a disastrous hack in 2017 that made 147 million Americans’ private financial information public. SSNs, credit card numbers, addresses, and dates of birth were among the compromised data. The company’s refusal to patch a known vulnerability in the popular web application framework Apache Struts caused the intrusion. Congressional hearings, a $700 million settlement, and the departure of key executives were the outcomes of Equifax’s heavy public and governmental scrutiny. This hack turned into a historic instance that highlighted how costly it is to overlook cybersecurity fundamentals.

8. Capital One 106 million customers (2019)

When a former AWS employee used an insecure firewall to gain access to private information kept on Amazon Web Services, Capital One suffered a significant breach in 2019. Approximately 106 million people in the United States and Canada were impacted by the disaster. Social Security numbers, bank account numbers, credit ratings, and names were among the data. Even while the breach was promptly discovered and stopped, it brought to light two important problems: the difficulties in protecting cloud-based infrastructure and the increasing danger of insider attacks. Before the perpetrator was apprehended, significant weaknesses in Capital One’s security posture were discovered.

9. MOVEit Transfer Hack (2023–2024)

The MOVEit Transfer hack, one of the worst supply chain attacks in recent memory, happened when the Cl0p ransomware group took advantage of a zero-day vulnerability. The BBC, Shell, American government freelancers, British Airways, and more than 200 more organizations were affected. Highly sensitive consumer and employee data was stolen using a popular file sharing program in the incident. Due to MOVEit’s integration into numerous major corporations’ supply chains, the hack had a significant impact on both the public and private sectors. This event highlighted how vital it is to secure software supply chains and third-party tools.

10. Canva 137 million users (2019)

In May 2019, a hacker claimed by the name “GnosticPlayers,” who was also behind a number of previous high-profile hacks, gained access to the Australian design platform Canva. 137 million users’ names, email addresses, usernames, and salted and hashed passwords were among the data that the attacker obtained. In a timely manner, Canva notified users and reset passwords. The long-term effects of the breach were comparatively lessened because of their prompt response and transparency. Even still, it was a reminder that cybercriminals find creative and SaaS systems appealing, particularly when managing large amounts of user-generated material.

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Conclusion

In the highly interconnected society of today, data is a valuable resource as well as a target. No company is immune, despite of size or industry, as shown by the top breaches we’ve examined, which include industry titans like Yahoo, Facebook, Aadhaar, and MOVEit. Along with causing identity theft and monetary loss, these incidents have damaged public confidence and exposed serious weaknesses in digital security systems.