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High 8.6Published Sep 17, 2026
CVE-2026-78501Microsoft 365 Copilot Business Chat Information Disclosure Vulnerability
Updated under an hour ago ()
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It affects Microsoft 365 Copilot's Business Chat and 1 other product. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 8.6 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N/E:U/RL:O/RC:C
- Weakness (CWE)
- CWE-77, CWE-923
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- microsoft
- NVD analysis
- Modified
- Record last updated
- Oct 14, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Microsoft Microsoft 365 Copilot's Business Chat microsoft:365_copilot_s_business_chat (from the name) | - | CNA record |
microsoft 365_copilot_chat microsoft:365_copilot_chat | all versions | NVD |
References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-78501vendor-advisory, patch
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.