Houghton Mifflin Harcourt Company
Attack Intelligence
Houghton Mifflin Harcourt Company was compromised in a ransomware attack attributed to shinyhunters in May 2026. The organization, operating in the Education sector in United States, was added to the group's data leak site as part of an extortion campaign.
shinyhunters operates as a financially motivated ransomware-as-a-service (RaaS) operation, exfiltrating sensitive data and threatening public disclosure to pressure victims into paying ransom demands.
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.
Intelligence correlations link this incident to 1 vulnerability(ies) including CVE-2026-35273, which may have been leveraged as initial access vectors or for lateral movement.