Synthient Credential Stuffing Threat Data Breach
What Happened
During 2025, the threat-intelligence firm Synthient aggregated 2 billion unique email addresses disclosed in credential-stuffing lists found across multiple malicious internet sources. Comprised of email addresses and passwords from previous data breaches, these lists are used by attackers to compromise other, unrelated accounts of victims who have reused their passwords. The data also included 1.3 billion unique passwords, which are now searchable in Pwned Passwords. Working to turn breached data into awareness, Synthient partnered with HIBP to help victims of cybercrime understand their exposure.
Compromised Data
Recommended Actions
Change Your Password
If you haven’t already changed the password affected by this breach, do so immediately on every account where it was used.
Enable Two-Factor Authentication
Wherever 2FA is supported, add an extra layer of security to your account.
Get Guardio for real-time protection after a breach. Guardio blocks AI-generated scam sites, fake login pages, and malicious pages designed to exploit leaked information. Built by cybersecurity specialists who track new threats 24/7, Guardio gives you immediate, expert-level protection plus clear steps to help you secure your accounts instantly.
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Use a password manager to generate and store strong, unique passwords for all your accounts. 1Password helps protect your data with industry-leading security.
Try 1Password
Get Aura for identity theft and credit protection. Keep your assets safe with fast fraud alerts, instant credit lock, and $1,000,000 identity theft insurance. Speak to a U.S. based fraud specialist 24/7.
Try AuraBreach Overview
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Affected Accounts:
2 billion
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Breach Occurred:
April 2025
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Added to HIBP:
6 Nov 2025
Recommended Actions
Change Your Password
If you haven’t already changed the password affected by this breach, do so immediately on every account where it was used.
Enable Two-Factor Authentication
Wherever 2FA is supported, add an extra layer of security to your account.
Use a password manager to generate and store strong, unique passwords for all your accounts. 1Password helps protect your data with industry-leading security.
Try 1Password
Get Aura for identity theft and credit protection. Keep your assets safe with fast fraud alerts, instant credit lock, and $1,000,000 identity theft insurance. Speak to a U.S. based fraud specialist 24/7.
Try Aura
Get Guardio for real-time protection after a breach. Guardio blocks AI-generated scam sites, fake login pages, and malicious pages designed to exploit leaked information. Built by cybersecurity specialists who track new threats 24/7, Guardio gives you immediate, expert-level protection plus clear steps to help you secure your accounts instantly.
Try Guardio