The Tumblr Dump: 62M Stolen Login Credentials Hit the Dark Web

Tumblr is a social media and microblogging platform that gained widespread popularity in the late 2000s and early 2010s for creative content, art, and blogging communities. In February 2013, Tumblr's database was breached, exposing 62,259,218 user accounts. The stolen data includes email addresses, SHA-1 password hashes, and a hash type field. The breach is verified. The passwords were stored using SHA-1 hashing with salts, but this breach copy is noted as having missing salts, which significantly reduces the protection salting is meant to provide and makes the hashes easier to crack.

Why Tumblr Breach Is Dangerous

SHA-1 is no longer considered a secure hashing algorithm for passwords, and 62 million records represent one of the larger breach datasets from 2013. The missing salts note is particuarly significant: salting is the technique that makes each identical password produce a different hash, which prevents mass cracking with precomputed tables. Without salts, attackers can use rainbow tables to crack common passwords across the entire 62-million-record database simultaneously rather than one account at a time. This means the most common passwords in this dataset may already be known in plain text.

What Was Exposed in the Tumblr Leak

• Email Address
• SHA-1 Password Hash
• Hash Type Identifier

Why This Tumblr Data Puts You at Risk

Tumblr was a mainstream social platform used by tens of millions of people, many of whom registered with a primary personal email address they still use today. If you had a Tumblr account in 2013 and used the same password on any other platform, that password may have been cracked. Tumblr users who never received breach notifications or forgot they had an account are at particular risk, because they have no reason to have updated that password. Credential stuffing tools automaticaly test known email-password pairs against current banking, shopping, and social media platforms.

How the Tumblr Breach Gets Used in Modern Attacks

The Tumblr breach occured in 2013 but was not publicly disclosed until 2016, creating a three-year window during which the data circulated privately. By the time users were notified, the credentials had been widely distributed. Today, the 62-million-record Tumblr dataset remains one of the larger social media breaches available in underground markets. It is frequently used as a starting point for large-scale credential stuffing campaigns because Tumblr users represent a broad cross-section of the internet-using population from that era, many of whom reused passwords across multiple services they still rely on.

Check If Your Data Was Exposed

HEROIC's free breach search checks your email against 400 billion+ compromised records, including the Tumblr dataset. Search now to see if your account was part of this breach. If you had a Tumblr account before 2016 and have not changed any passwords you used in 2013, update those accounts today and enable two-factor authentication wherever it is available.