Microsoft Office Excel: Out-of-bounds read enables remote code execution
Summary
Microsoft Office Excel contains an out-of-bounds read vulnerability (CWE-125, CWE-191) that allows an unauthorized attacker to execute code over a network. According to the CVSS vector (AV:N/PR:N/UI:R), no privileges are required, but a user must interact, most likely by opening a crafted spreadsheet from email or a file share. Microsoft is the CNA, and NVD analysis was still pending when the record was published.
Affected
- Microsoft 365 Apps for Enterprise: from 16.0.1, before the build on Microsoft's release page (aka.ms/OfficeSecurityReleases)
- Office 365 for Mac: from 1.0.0, before 16.115.26110837
- Office LTSC 2021: from 16.0.1, before 16.0.14334.21048
- Office LTSC 2024: before 16.0.17932.21140 (aggregator data, unverified)
- Office LTSC for Mac 2021: from 16.0.1, before 16.115.26110837
- Office LTSC for Mac 2024: from 16.0.0, before 16.115.26110837
- Office Online Server: before 16.0.10417.20236 (likely affected, not confirmed by MSRC)
Fixed in
- Office 365 for Mac: 16.115.26110837 (per CNA record)
- Office LTSC for Mac 2021 and 2024: 16.115.26110837 (per CNA record)
- Office LTSC 2021: 16.0.14334.21048 (per CNA record)
- Office LTSC 2024: 16.0.17932.21140 (unverified against MSRC)
- Microsoft 365 Apps for Enterprise: current build per Microsoft release page
- Office Online Server: Unknown
Workaround
Unknown.
Exploitation
- CISA SSVC: exploitation none, automatable no, technical impact total
- No evidence of exploitation in the wild found
- Microsoft's "Exploited" flag not found
- No public proof-of-concept found
Our recommendation
- Install the November 2026 Office security updates on all affected Office installations, prioritising Office Online Server and machines that regularly open external spreadsheets
- Verify build numbers against the MSRC advisory before rollout
- Restrict or sandbox opening of spreadsheets from untrusted email and file shares
- Check whether Office Online Server is deployed and published to the internet
- Monitor for exploitation indicators and updates to the NVD entry
Information from Microsoft (Patch Tuesday November 2026)
- Severity (Microsoft)
- Important
- Impact
- Remote code execution – 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 Update Guide (MSRC) msrc.microsoft.com
- CVE Record (CVE.org, Microsoft CNA) www.cve.org
- Strix AI CVE entry www.strix.ai
- ThreatInt CVE entry cve.threatint.com
- Stefan Gossner: SharePoint security fixes, November 2026 PU blog.stefan-gossner.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 10 Nov 2026, 22:06.
Original description (NVD)
Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to execute code 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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