What is CVE-2026-26129?

CVE-2026-26129 is a security advisory published by Microsoft Security Response Center (MSRC) with Critical severity. M365 Copilot Information Disclosure Vulnerability

Which CVE IDs does CVE-2026-26129 cover?

CVE-2026-26129 covers the following CVE IDs: CVE-2026-26129. Each CVE has its own detail page on EchelonGraph Pulse with the synthesized EG score.

What is the CVSS v3 score of CVE-2026-26129?

CVE-2026-26129 has a CVSS v3 base score of 7.5, published by Microsoft Security Response Center (MSRC).

Which products are affected by CVE-2026-26129?

CVE-2026-26129 affects 1 product, including: Microsoft 365 Copilot's Business Chat.

CVE-2026-26129CriticalCVSS 7.5

M365 Copilot Information Disclosure Vulnerability

Vendor

Microsoft Security Response Center (MSRC)

Published

May 22, 2026

Last Modified

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🔗 CVE IDs covered (1)

CVE-2026-26129 →

📋 Description

Improper neutralization of special elements used in a command ('command injection') in M365 Copilot allows an unauthorized attacker to disclose information over a network.

🎯 Affected products1

Microsoft 365 Copilot's Business Chat

🔗 References (1)

advisoryhttps://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-26129