Description
Improper neutralization of special elements in output used by a downstream component ('injection') in M365 Copilot allows an unauthorized attacker to disclose information over a network.
References (1)
Core 1
Core References
Vendor Advisory vendor-advisory
patch
M365 Copilot Information Disclosure Vulnerability
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-26164
Scores
CVSS v3
7.5
EPSS
0.0010
EPSS Percentile
26.7%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
CISA SSVC
Vulnrichment
Exploitation
none
Automatable
yes
Technical Impact
partial
Details
CWE
CWE-74
Status
published
Products (2)
microsoft/365_copilot_chat
Microsoft/Microsoft 365 Copilot's Business Chat
-
Published
May 07, 2026
Tracked Since
May 08, 2026