Varonis found a “Reprompt” attack that let a single link hijack Microsoft Copilot Personal sessions and exfiltrate data; Microsoft patched it in January 2026.

Reprompt impacted Microsoft Copilot Personal and, according to the team, gave "threat actors an invisible entry point to perform a data‑exfiltration chain that bypasses enterprise security controls ...

I'm not okay with that idea, so I determined that it was time that I started building up my own dedicated database of ...