At Black Hat USA 2026, researchers Ori Lahav and Dan Avraham of Rubrik Zero Labs detailed a new vulnerability class termed Remote Prompt Execution (RPE), demonstrated on Microsoft 365 Copilot. A five-stage exploit chain transforms a prompt injection into a persistent, bidirectional interactive shell, starting with a poisoned Word document containing hidden white-on-white text that bypasses LLM safety guardrails. The chain exploits CVE-2026-32193, a path traversal flaw (CWE-22) in Microsoft Azure Kubernetes Service with a CVSS score of 8.8 and a $48,000 bug bounty, patched in the June 2026 security update. The exploit uses the Azure Container Apps dynamic sessions and an LD_PRELOAD exploit to escape the sandbox, granting the attacker the victim’s identity, permissions, and access to enterprise data sources like M365 and Azure. The technical blog, authored by Kyle Fiehler and published on Rubrik Zero Labs on July 30, 2026, notes the vulnerability was reported to and fixed by Microsoft before public disclosure, and the ChatMate proof-of-concept is not an active in-the-wild exploit. RPE follows a pattern of summer vulnerabilities: CVE-2026-9198 in IBM Langflow triggered a CISA emergency deadline, CVE-2026-33017 was exploited within 20 hours of disclosure, and CVE-2026-55255 harvested LLM provider keys. Unit