cve 2026 24307

CVE-2026-24307, also known as the Reprompt vulnerability, is a high-impact information-disclosure flaw in Microsoft's Copilot Personal assistant. Discovered by Varonis Threat Labs, it exploits a design weakness in how Copilot handles prompt content embedded in links. A single-click chain could trick Copilot into leaking small pieces of user context and session data to an attacker-controlled endpoint. Microsoft addressed the issue during the January 2026 update cycle. The incident highlights ongoing engineering and operational challenges with general-purpose LLM assistants, particularly around prompt injection and data security. This tag covers discussions, disclosures, and mitigations related to CVE-2026-24307 on WindowsForum.