PT-2026-2756 · Microsoft · Office Excel

Jmini + 1 · Published 2026-01-13 · Updated 2026-01-19 · CVE-2026-20957

Positive Technologies (AI Summary)

CVSS v3.1

7.8

High

Base vector

AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Name of the Vulnerable Software and Affected Versions Microsoft Office Excel (affected versions not specified)

Description An integer underflow condition exists in Microsoft Office Excel that could allow an unauthorized attacker to execute code locally. The issue is due to an integer underflow, also known as a wrap or wraparound.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.

RCE

Integer Underflow

Heap Based Buffer Overflow

Weakness Enumeration

CWE-191

CWE-122

Related Identifiers

BDU:2026-00401

CVE-2026-20957

Affected Products

Office Excel

References · 7

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20957 · Vendor Advisory
• http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-20957 · Security Note
• https://nvd.nist.gov/vuln/detail/CVE-2026-20957 · Security Note
• https://bdu.fstec.ru/vul/2026-00401 · Security Note
• https://osv.dev/vulnerability/CVE-2026-20957 · Vendor Advisory
• https://twitter.com/CVEnew/status/2011142886440472883 · Twitter Post
• https://twitter.com/The_SatyaDVV/status/2013126685756203243 · Twitter Post