Microsoft Office Excel: Out-of-bounds read leads to information disclosure
Summary
A out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to disclose information over a network. Exploitation requires that a user opens a crafted file, typically one received by email or downloaded from the web. The impact is limited to confidentiality, as leaked memory may contain sensitive data from the session or document; code execution is not reported for this flaw.
Affected
- Microsoft 365 Apps for Enterprise (32/64-bit): from 16.0.1 before the build listed at aka.ms/OfficeSecurityReleases
- Office 365 for Mac: from 1.0.0 before 16.115.26110837
- Office LTSC 2021 (32/64-bit): from 16.0.1 before 16.0.14334.21048
- Office LTSC 2024: from 16.0.0 before 16.0.17932.21140 (unverified against MSRC)
- Office LTSC for Mac 2021 and 2024, Office Online Server: listed only in a third-party mirror (unverified)
Fixed in
- Office 365 for Mac: 16.115.26110837
- Office LTSC 2021: 16.0.14334.21048
- Office LTSC 2024: 16.0.17932.21140 (unverified against MSRC)
- Microsoft 365 Apps for Enterprise: build not stated in the CNA record; check the MSRC advisory
- Fixes released on 10 November 2026
Workaround
Unknown.
- No vendor workaround identified.
- Keep Protected View enabled for files from email and the internet.
Exploitation
- No evidence of exploitation in the wild found.
- No public proof of concept found.
- CISA SSVC: exploitation none, automatable no.
- CVSS temporal vector includes E:U (exploit maturity unproven).
Our recommendation
- Confirm the exact fixed build for each Office channel in the MSRC advisory.
- Roll out the November 2026 Office security update, prioritising LTSC 2021 installations that are deferred and Excel-heavy users.
- Keep Protected View enabled and restrict macros and external content from untrusted sources.
- Monitor NVD and CISA KEV for status changes, as the NVD status is currently awaiting analysis.
Information from Microsoft (Patch Tuesday November 2026)
- Severity (Microsoft)
- Important
- Impact
- Information disclosure – Microsoft Office Excel
- Status on Patch Tuesday
- Neither exploited nor publicly disclosed
- Exploitability assessment
- Exploitation less likely
- Product family
- Microsoft Office
- Updates (KB)
- KB5002946
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Microsoft Security Response Center advisory msrc.microsoft.com
- CVE Record (CVE.org) www.cve.org
- Microsoft 365 Apps security updates learn.microsoft.com
- CVE mirror (ThreatInt) cve.threatint.com
- Rapid7 Patch Tuesday November 2026 www.rapid7.com
- Talos Patch Tuesday November 2026 blog.talosintelligence.com
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 11 Nov 2026, 12:12.
Original description (NVD)
Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to disclose information over a network.
NVD references (1)
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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