CVE-2026-20957

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

CVSS v3 7.8 HIGH

7.8^/10

CVSS v3 : HIGH

Vector :

Exploitability : 1.8 / Impact : 5.9

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required NONE

User Interaction REQUIRED

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20957	Vendor Advisory

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:microsoft:365_apps:-::::enterprise::x64:*
	cpe:2.3:a:microsoft:365_apps:-::::enterprise::x86:*
	cpe:2.3:a:microsoft:excel:2016:::::::*
	cpe:2.3:a:microsoft:office:2019:::::::*
	cpe:2.3:a:microsoft:office_long_term_servicing_channel:2021:::::-:x64:*
	cpe:2.3:a:microsoft:office_long_term_servicing_channel:2021:::::-:x86:*
	cpe:2.3:a:microsoft:office_long_term_servicing_channel:2021:::::macos::
	cpe:2.3:a:microsoft:office_long_term_servicing_channel:2024:::::-:x64:*
	cpe:2.3:a:microsoft:office_long_term_servicing_channel:2024:::::-:x86:*
	cpe:2.3:a:microsoft:office_long_term_servicing_channel:2024:::::macos::
	cpe:2.3:a:microsoft:office_online_server::::::::

History

No history.

Information

Published : 2026-01-13 18:16

Updated : 2026-01-14 19:47

NVD link : CVE-2026-20957

Mitre link : CVE-2026-20957

CVE.ORG link : CVE-2026-20957

JSON object : View

Products Affected

microsoft

365_apps
office_long_term_servicing_channel
office
excel
office_online_server

CWE

CWE-122

Heap-based Buffer Overflow

CWE-191

Integer Underflow (Wrap or Wraparound)

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