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7.8
HIGH CVSS 3.1
CVE-2026-20957
Microsoft Excel Remote Code Execution Vulnerability
Description

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

INFO

Published Date :

Jan. 13, 2026, 6:16 p.m.

Last Modified :

Jan. 14, 2026, 7:47 p.m.

Remotely Exploit :

No

Source :

[email protected]
Affected Products

The following products are affected by CVE-2026-20957 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Microsoft office
2 Microsoft 365_apps
3 Microsoft excel
4 Microsoft office_online_server
5 Microsoft office_long_term_servicing_channel
6 Microsoft office_macos_2024
7 Microsoft office_macos_2021
8 Microsoft excel_2016
9 Microsoft office_2024
10 Microsoft office_2021
11 Microsoft office_2019
: Total Affected Vendor : 1 | Products : 11
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 3.1 HIGH f38d906d-7342-40ea-92c1-6c4a2c6478c8
CVSS 3.1 HIGH [email protected]
Solution
Apply Microsoft security updates to fix an Excel integer underflow vulnerability.
  • Apply security update 5002824.
  • Apply security update KB5002831.
  • Update Office for Mac to version 16.105 or later.
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2026-20957.

URL Resource
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20957 Vendor Advisory
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-20957 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-20957 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-20957 vulnerability anywhere in the article.

  • CrowdStrike.com
January 2026 Patch Tuesday: 114 CVEs Patched Including 3 Zero-Days

Microsoft has addressed 114 vulnerabilities in its January 2026 security update release, including 112 newly patched CVEs and 2 updated advisories. This month's update addresses one actively exploited ... Read more

Published Date: Jan 14, 2026 (2 weeks, 5 days ago)
  • TheCyberThrone
Microsoft Patch Tuesday – January 2026

January 14, 2026Microsoft’s January 13, 2026, Patch Tuesday release addresses 114 vulnerabilities, including one actively exploited zero-day in Desktop Window Manager, eight critical flaws, and three ... Read more

Published Date: Jan 14, 2026 (2 weeks, 5 days ago)
  • Daily CyberSecurity
Patch Tuesday Jan 2026: Microsoft Fixes 114 Flaws & 3 Zero-Days

Microsoft has kicked off 2026 with a massive security update, addressing a total of 114 vulnerabilities in its January Patch Tuesday release. The update includes eight critical flaws and 106 important ... Read more

Published Date: Jan 14, 2026 (2 weeks, 5 days ago)
  • Zero Day Initiative
The January 2026 Security Update Review

I may be in Tokyo preparing for Pwn2Own Automotive, but that doesn’t stop patch Tuesday from coming. Put aside you broken New Year’s resolutions for just a moment as we review the latest security patc ... Read more

Published Date: Jan 13, 2026 (2 weeks, 6 days ago)
  • BleepingComputer
Microsoft January 2026 Patch Tuesday fixes 3 zero-days, 114 flaws

Today is Microsoft's January 2026 Patch Tuesday with security updates for 114 flaws, including one actively exploited and two publicly disclosed zero-day vulnerabilities.This Patch Tuesday also addres ... Read more

Published Date: Jan 13, 2026 (2 weeks, 6 days ago)
  • CybersecurityNews
Microsoft Patch Tuesday January 2026 – 114 Vulnerabilities Fixed Including 3 Zero-days

CVE-2026-20822Windows Graphics Component Elevation of Privilege VulnerabilityElevation of PrivilegeCVE-2026-20876Windows Virtualization-Based Security (VBS) Enclave Elevation of Privilege Vulnerabilit ... Read more

Published Date: Jan 13, 2026 (2 weeks, 6 days ago)

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2026-20957 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • Initial Analysis by [email protected]

    Jan. 14, 2026

    Action Type Old Value New Value
    Added CPE Configuration OR *cpe:2.3:a:microsoft:excel:2016:*:*:*:*:*:*:* *cpe:2.3:a:microsoft:office:2019:*:*:*:*:*:*:* *cpe:2.3:a:microsoft:365_apps:-:*:*:*:enterprise:*:x64:* *cpe:2.3:a:microsoft:365_apps:-:*:*:*:enterprise:*:x86:* *cpe:2.3:a:microsoft:office_long_term_servicing_channel:2021:*:*:*:*:macos:*:* *cpe:2.3:a:microsoft:office_long_term_servicing_channel:2024:*:*:*:*:macos:*:* *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:2024:*:*:*:*:-:x64:* *cpe:2.3:a:microsoft:office_long_term_servicing_channel:2024:*:*:*:*:-:x86:* *cpe:2.3:a:microsoft:office_online_server:*:*:*:*:*:*:*:* versions up to (excluding) 16.0.10417.20083
    Added Reference Type Microsoft Corporation: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20957 Types: Vendor Advisory
  • New CVE Received by [email protected]

    Jan. 13, 2026

    Action Type Old Value New Value
    Added Description Integer underflow (wrap or wraparound) in Microsoft Office Excel allows an unauthorized attacker to execute code locally.
    Added CVSS V3.1 AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
    Added CWE CWE-191
    Added CWE CWE-122
    Added Reference https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20957
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
Vulnerability Scoring Details
Base CVSS Score: 7.8
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality Impact
Integrity Impact
Availability Impact