Houghton Mifflin Harcourt Company
About the organisation
Your data was compromised in several of our campaigns throughout the past few months. We urge you to engage with us, it is in your best interests. This is a final warning to reach out by 12 May 2026 before we leak along with several annoying (digital) problems that'll come your way. Make the right decision, don't be the next headline. | Updated: 9 May 2026 | Warning: FINAL WARNING PAY OR LEAK
What the listing means
Houghton Mifflin Harcourt Company appeared on the shinyhunters leak site on 09 May 2026. Groups publish a victim once negotiations stall or as pressure during them, so a listing usually means data was already exfiltrated. This group has published 3 claims in the last 30 days and remains active.
Recommended actions
- Treat any unsolicited message referencing Houghton Mifflin Harcourt Company as suspicious — leaked data gets weaponised for phishing within days.
- If you hold an account on hmhco.com, change that password now, update it anywhere you reused it, and enable two-factor authentication.
- Other Education organisations should review this group's known TTPs and validate detection coverage against them.
- Watch for follow-on extortion: stolen data is often re-leaked or resold after the initial listing.
- A leak-site listing is a claim made by the attacker, not a confirmed breach — check the organisation's own disclosures before acting on it.
Leak-site evidence
Listing URL https://www.ransomware.live/id/SG91Z2h0b24gTWlmZmxpbiBIYXJjb3VydCBDb21wYW55QHNoaW55aHVudGV...