CVE-2026-20957

high Microsoft
CVSS v3 Base Score
7.8
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS Score
0.1%
Exploitation probability in 30 days
Top 77% most likely to be exploited
Attack Characteristics
Attack Vector
Local
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Confidentiality
High
Integrity
High
Availability
High
Published: January 13, 2026 (121 days ago)
Last Modified: January 14, 2026
Vendor: Microsoft

Description

Integer underflow (wrap or wraparound) in Microsoft Office Excel allows an unauthorized attacker to execute code locally.

CWE

CWE-122

Affected Products

microsoft 365 appsmicrosoft excelmicrosoft officemicrosoft office long term servicing channelmicrosoft office online server

References

🔗 msrc.microsoft.com