Mainstream Bulgaria – Cybersecurity Incident

Sofia, September 26, 2025 – On Monday, September 22, at 02:17 EET, Mainstream Bulgaria experienced a cyber incident that resulted in a temporary service disruption.

Our team immediately launched our incident response protocols to contain the incident, initiate recovery measures and prioritize the continuity of our clients’ operations.

An investigation is ongoing. We have notified the relevant stakeholders in line with our compliance obligations, and we are working closely with independent cybersecurity experts to establish the full circumstances of the incident. Their findings will inform all necessary remediation and prevention measures.

Restoring full functionality remains our highest priority. We are committed to minimizing operational impact, protecting customer data, and strengthening the resilience of our digital infrastructure.

Importantly, our operations in other countries have not been affected and continue without interruption.

Cyberattacks are an unfortunate reality for companies worldwide, and Mainstream continues to prioritize investment in the security and resilience of its digital infrastructure.

We sincerely apologize for any inconvenience this incident may have caused and thank our customers and partners for their understanding and trust. We will continue to communicate transparently and provide updates as appropriate.