Microsoft 365 Copilot S Business Chat

Remote unauthenticated attackers can disclose sensitive information from Microsoft 365 Copilot's Business Chat through improper input neutralization (CVSS 7.5). The vulnerability allows network-based exploitation with low complexity and no user interaction required. Vendor-released patch available via Microsoft Security Response Center (MSRC-2026-26129). No public exploit identified at time of analysis, though the low attack complexity (AC:L) and lack of authentication requirements (PR:N) increase realistic exploitation risk.

Injection vulnerability in Microsoft 365 Copilot's Business Chat enables remote unauthenticated attackers to extract sensitive information through specially crafted inputs. Microsoft has released a patch addressing this CWE-74 injection flaw. With CVSS 7.5 (High), network-accessible attack vector, and no authentication required, this represents a significant exposure for organizations using Copilot Business Chat, though no active exploitation is confirmed at time of analysis.