Vulnerability · CVE-2026-78501
Microsoft 365 Copilot Business Chat Information Disclosure Vulnerability
Published Sep 17, 2026 · catalog updated Oct 14, 2026 · Microsoft Microsoft 365 Copilot's Business Chat
Check if you run it
No confirmed exploitation is on record for CVE-2026-78501. EPSS is 0.54%. Act only if a listed version of Microsoft Microsoft 365 Copilot's Business Chat is installed.
Gaps on this record
- No version range is stored. A customer cannot check an installed version against this record.
- No vendor fix or required action is stored. Compare the linked advisory before you change production.
- Severity
- High8.6
- Known exploitation
- Not in CISA/VulnCheck KEV
- EPSS
- 0.54%
- Remediation
- Advisory link
- Affected products
- cpe microsoft/365 copilot chat · vendor Microsoft Microsoft 365 Copilot's Business Chat
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.
Are you affected?
Enter the version you run. The result uses only the ranges stored on this record.
The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.
- cpe microsoft/365 copilot chatversion unspecified
- vendor Microsoft Microsoft 365 Copilot's Business Chatversion unspecified
How to fix CVE-2026-78501
Recommended remediation
A patch or advisory reference is linked. Open the original publisher for availability by product version.
Official advisories
What to do
Three questions, each answered from this record only. Confirm the vendor advisory before you patch.
Should you patch?
No confirmed exploitation is on record for CVE-2026-78501. EPSS is 0.54%. Act only if a listed version of Microsoft Microsoft 365 Copilot's Business Chat is installed.
Which versions are affected?
Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.
What should an analyst verify?
CWE-77: Command Injection; CWE-923. EPSS 0.54%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.
Code
The project this record applies to. Exploit listings stay in References.
No public source repository is identified for this product.
Timeline
Detection, updates, and resolution for this record.
Sep 17, 2026 · NIST NVD
Detected
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.
Oct 14, 2026 · NIST NVD
Updated
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.
Sources
- CIRCL Vulnerability LookupVulnerability recordCVE-2026-78501
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.
vulnerability.circl.lu - CVE.orgVulnerability recordCVE-2026-78501
Official CVE identifier
cve.org - FIRST EPSSExploitation probabilityCVE-2026-78501
30-day exploitation probability 0.5%
first.org - NIST NVDVulnerability recordCVE-2026-78501
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.
nvd.nist.gov
References
Freshness
Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.