Trellix

Trellix is a cybersecurity detection and response vendor formed in January 2022 through the merger of McAfee Enterprise and FireEye, both acquired by private equity firm Symphony Technology Group (STG). On 8 May 2026, Trellix disclosed that an unauthorised party — later identified as RansomHouse — had accessed part of its source-code repository on 17 April, a 21-day intrusion-to-disclosure gap. No data from the breach had appeared publicly as of the disclosure date.

Trellix produces endpoint detection and response (EDR), email security, network detection, and threat-intelligence products. Its customer base includes UK Government departments and critical national infrastructure operators, making source-code access potentially significant for adversaries seeking to understand detection signatures or identify sensor blind spots. The company markets itself as a successor to the threat-intelligence pedigree of FireEye's Mandiant division, though Mandiant itself was sold to Google in 2022 before the Trellix merger completed.

The 21-day disclosure timeline sits outside the 24-hour initial-notification window proposed by the UK Cyber Security and Resilience Bill. The breach raises questions about whether Trellix's own detection tooling flagged the intrusion promptly, given the reputational sensitivity of a security vendor failing to detect an attacker inside its own systems.