securityaffairs.com 8/17/2026, 12:21:06 AM · external

Threema hit by DDoS attack, causing four hour messaging outage

Threema hit by DDoS attack, causing four hour messaging outage
CyberSIXT Evidence Panel
Primary Source threema.com

THREEMA , a Swiss secure messaging service, faced significant disruptions due to multiple large-scale DDoS attacks that affected communication services, although on-premise users were unaffected. Users reported outages starting on Tuesday evening, initially attributed to a network issue, but confirmed as DDoS attacks later. The service experienced about four hours of downtime and intermittent issues were reported the following day. Threema's colocation partner was also targeted, complicating mitigation efforts.

The company has since deployed additional DDoS protection and plans to enhance its status page to provide users with better service update access.

View Primary Source Via securityaffairs.com

Article by CyberSIXT