Large-Scale DDoS Attacks Disrupt Threema Messaging Service

Threema, a secure messaging service, experienced significant disruptions due to multiple large-scale DDoS attacks earlier this week. Users reported outages starting on August 15, 2026, particularly affecting those in Switzerland, India, and China. Organizations using Threema On-Prem were unaffected as they operate on their own infrastructure. The attacks were characterized by a constantly changing pattern, making them difficult to mitigate. Threema confirmed that both its service and its colocation partner, Nine, were targeted. Users faced intermittent outages, and the company had to take its system status page offline due to unrelated technical issues. To prevent future incidents, Threema has implemented specialized DDoS protection measures. The company communicated with business customers about the unstable service conditions during the attacks.

Key Points: • Threema faced multiple large-scale DDoS attacks causing severe service disruptions. • Users in Switzerland, India, and China reported significant outages starting August 15, 2026. • Organizations using Threema On-Prem were not affected due to their independent infrastructure.