Mastodon and Bluesky: Mastodon says its flagship server was hit by a DDoS attack

Mastodon’s Flagship Server Hit by DDoS Attack, Causing Temporary Outages

Mastodon’s primary server, mastodon.social, was targeted by a distributed denial-of-service (DDoS) attack on Monday, rendering the instance intermittently inaccessible. Users encountered error messages or full-screen outage warnings as the platform struggled under the assault.

Mastodon acknowledged the attack in a status update at approximately 7 a.m. ET, confirming it was investigating the incident. By 9:05 a.m. ET, the team implemented countermeasures, restoring access, though some instability persisted as the attack continued.

The attack follows a similar DDoS incident targeting Bluesky, another decentralized social network, which experienced days-long outages before stabilizing on April 16. Mastodon reported that the attack involved millions of malicious requests, consistent with a DDoS pattern, but only mastodon.social was affected other instances in the Fediverse remained operational.

Andy Piper, Mastodon’s head of communications, highlighted the resilience of decentralized networks, noting that users on other servers were unaffected and could continue posting without disruption. DDoS attacks overwhelm servers with junk traffic, causing outages without stealing data. While disruptive, their impact on decentralized platforms like Mastodon and Bluesky is often limited to specific instances rather than the entire network.

Source: https://techcrunch.com/2026/04/20/mastodon-says-its-flagship-server-was-hit-by-a-ddos-attack/

Mastodon cybersecurity rating report: https://www.rankiteo.com/company/joinmastodon

Bluesky Social cybersecurity rating report: https://www.rankiteo.com/company/bluesky-pbc

"id": "JOIBLU1776719420",
"linkid": "joinmastodon, bluesky-pbc",
"type": "Cyber Attack",
"date": "4/2026",
"severity": "25",
"impact": "1",
"explanation": "Attack without any consequences"

{'affected_entities': [{'customers_affected': 'Users of mastodon.social '
                                              'instance',
                        'industry': 'Technology / Social Networking',
                        'name': 'Mastodon (mastodon.social)',
                        'type': 'Social Media Platform'}],
 'attack_vector': 'Distributed Denial-of-Service (DDoS)',
 'customer_advisories': 'Users informed via status updates about the outage '
                        'and resolution.',
 'date_detected': '2023-04-17T07:00:00Z',
 'date_publicly_disclosed': '2023-04-17T07:00:00Z',
 'date_resolved': '2023-04-17T09:05:00Z',
 'description': 'Mastodon’s primary server, *mastodon.social*, was targeted by '
                'a distributed denial-of-service (DDoS) attack on Monday, '
                'rendering the instance intermittently inaccessible. Users '
                'encountered error messages or full-screen outage warnings as '
                'the platform struggled under the assault. The attack involved '
                'millions of malicious requests, consistent with a DDoS '
                'pattern, but only *mastodon.social* was affected; other '
                'instances in the Fediverse remained operational.',
 'impact': {'downtime': 'Intermittent outages from ~07:00 ET to 09:05 ET',
            'operational_impact': 'Users unable to access the platform '
                                  'temporarily',
            'systems_affected': 'mastodon.social server'},
 'investigation_status': 'Resolved',
 'lessons_learned': 'Decentralized networks like Mastodon are resilient to '
                    'DDoS attacks, as only specific instances are affected '
                    'rather than the entire network.',
 'post_incident_analysis': {'corrective_actions': 'Countermeasures implemented '
                                                  'to restore access',
                            'root_causes': 'DDoS attack involving millions of '
                                           'malicious requests'},
 'references': [{'date_accessed': '2023-04-17',
                 'source': 'Mastodon Status Update'}],
 'response': {'communication_strategy': 'Status update acknowledging the '
                                        'attack and progress',
              'containment_measures': 'Countermeasures implemented to mitigate '
                                      'the attack',
              'incident_response_plan_activated': True,
              'recovery_measures': 'Access restored by 09:05 ET'},
 'title': 'Mastodon’s Flagship Server Hit by DDoS Attack, Causing Temporary '
          'Outages',
 'type': 'DDoS'}