CVE-2026-42827Network attack vector

Information disclosure via command injection

Published May 22, 2026 · Updated May 22, 2026

Command injection in Microsoft 365 Copilot allows remote attackers to disclose information over a network after user interaction. Microsoft has not published the affected command-processing locus, the untrusted input path, or how special elements reach a command. Exploitation requires user interaction but no attacker privileges, and the reported consequence is information disclosure only.

CVSS severity6.5
Medium
EPSS probability0.50%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Command injection in Microsoft 365 Copilot allows remote attackers to disclose information over a network after user interaction. Microsoft has not published the affected command-processing locus, the untrusted input path, or how special elements reach a command. Exploitation requires user interaction but no attacker privileges, and the reported consequence is information disclosure only.

The record

CVE
CVE-2026-42827
Published
May 22, 2026
Updated
May 22, 2026
Vendor
Microsoft
Product
Microsoft 365 Copilot
Classifications
CWE-77, T1059
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 22, 2026CVE publishedPublication date reported by the CVE source.
  2. May 22, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=-

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Microsoft · Microsoft 365 Copilotversion=-

Published CVSS scores

6.5Microsoft CorporationCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
5.7Microsoft Security Response CenterCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C
7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-77Improper Neutralization of Special Elements used in a Command ('Command Injection')
T1059Command and Scripting Interpreter

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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