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HIGH · 7.5

CVE-2026-26129

Improper neutralization of special elements in M365 Copilot allows an unauthorized attacker to disclose information over a network.

Vulnerability Description

Improper neutralization of special elements in M365 Copilot allows an unauthorized attacker to disclose information over a network.

CVSS Score

7.5

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
NONE
Availability
NONE

Affected Products

VendorProductVersions
Microsoft365 Copilot Chat-

Related Weaknesses (CWE)

CWE-138

References

FAQ

What is CVE-2026-26129?

CVE-2026-26129 is a vulnerability with a CVSS score of 7.5 (HIGH). Improper neutralization of special elements in M365 Copilot allows an unauthorized attacker to disclose information over a network.

How severe is CVE-2026-26129?

CVE-2026-26129 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-26129?

Check the references section above for vendor advisories and patch information. Affected products include: Microsoft 365 Copilot Chat.