CVE-2026-78501 Microsoft 365 Copilot Business Chat Information Disclosure Vulnerability
An attacker can exploit command injection in Microsoft 365 Copilot Business Chat to disclose sensitive information over the network.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-78501?
CVE-2026-78501 is a high-severity command injection vulnerability in Microsoft 365 Copilot's Business Chat, published on 17 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Improper neutralization of special elements used in a command ('command injection') in Microsoft 365 Copilot's Business Chat allows an unauthorized attacker to disclose information over a network.
Which versions are affected by CVE-2026-78501?
It affects 1 product.
Products include Microsoft 365 Copilot Chat.
How do I fix CVE-2026-78501?
No fix has been published for CVE-2026-78501 yet. Limit exposure of the affected software until one is available.
Upgrade, and pass arguments to programs as a list instead of through a shell. More about Command injection.
Is CVE-2026-78501 being exploited?
There is no known exploitation of CVE-2026-78501 in the wild and no public exploit code.
Other vulnerabilities in Microsoft 365 Copilot's Business Chat
- CVE-2026-26137 Microsoft Exchange Elevation of Privilege Vulnerability
- CVE-2025-59272 Copilot Information Disclosure Vulnerability
- CVE-2025-59286 Copilot Information Disclosure Vulnerability
- CVE-2025-53787 Microsoft 365 Copilot BizChat Information Disclosure Vulnerability
- CVE-2026-26129 M365 Copilot Information Disclosure Vulnerability
Sources
Also known as GHSA-hjj2-64g6-jw5p.