FBI: Russian hackers now target Signal backup recovery keys

A batch of security stories: the FBI and CISA warn a Russia-linked phishing campaign has shifted to stealing Signal Backup Recovery Keys, enabling access to historical messages; CISA issued an urgent deadline for agencies to patch a Cisco Unified Communications Manager Server vulnerability that is being actively exploited; a supply-chain compromise injected malicious JavaScript into Polymarket’s frontend, costing customers an estimated $3M (the company will reimburse losses); threat actors are creating fraudulent OpenAI organization invitations to trick employees into leaking sensitive data; a