Invading the UK's internal network and leaking some agent information.

On March 20, 2026, the hacker group Cardinal issued a statement via overseas social media, claiming to have infiltrated the internal network of the British Secret Intelligence Service (MI6) and obtained the agency's operational personnel roster deployed in Eastern Europe and the Commonwealth of Independent States (CIS). The group also disclosed detailed information of 18 agents and presented political demands to the British government based on this.

This marks the second incident of core personnel information leakage from MI6 in the past six months. According to data published on a dark web forum in December 2025, a personnel list marked as from MI6's internal systems had already been made public at that time, containing 2,573 records. The combination of these two leaks poses a severe security challenge to the human intelligence network of the UK's foreign intelligence agency. According to the statement released by the Cardinal group, it had previously demonstrated its ability to penetrate UK networks through the Skynet project. This time, it further disclosed the Operational Personnel Register for Eastern Europe and CIS obtained from within MI6.

Screenshots of the leaked document show it is marked as UK SECRET // UK EYES ONLY and is restricted by ORCON (Originator Controlled) rules. The document title is clearly stated as Operational Personnel Register (Eastern Europe & CIS), with the last update dated March 22, 2026.

The two leaks of MI6 personnel records cover information dimensions including real identities and operational deployments, and both include personnel who are still active. The authenticity of the data from both leaks cannot be confirmed at this time. If the authenticity of both datasets is ultimately verified, this would become one of the most severe personnel information leak incidents involving British intelligence agencies in recent years.

The Cardinal group has been very active recently, and the information it has released seems somewhat incredible. The possibility of fabrication cannot be ruled out. Such claims themselves constitute a new form of hybrid warfare tactic: creating cognitive confusion through verifiable unverifiability, imposing both psychological and technical pressure on adversaries between truth and falsehood.