Microsoft Excel: Use-after-free leads to remote code execution
Summary
Microsoft Excel, part of several Microsoft Office and Microsoft 365 editions, contains a use-after-free vulnerability (CWE-416). According to the CVE record, an unauthorized attacker can execute code over a network. User interaction is required, for example by opening a crafted file, and no privileges are needed.
Affected
- Microsoft 365 Apps for Enterprise: 16.0.1 before the fix in https://aka.ms/OfficeSecurityReleases (fixed build not stated in the record)
- Office LTSC 2021: 16.0.1 before 16.0.14334.21048
- Office LTSC 2024: 16.0.0 before 16.0.17932.21140 (per aggregator, unverified)
- Office 365 for Mac: 1.0.0 before 16.115.26110837
- Office LTSC for Mac 2021: 16.0.1 before 16.115.26110837
- Office LTSC for Mac 2024: 16.0.0 before 16.115.26110837
- Office Online Server: 16.0.0.0 before 16.0.10417.20236 (per aggregator, unverified)
Fixed in
- Office LTSC 2021: 16.0.14334.21048 (per CVE record)
- Office for Mac (Microsoft 365 and LTSC for Mac): 16.115.26110837 (per CVE record)
- Other builds: Unknown. The MSRC advisory could not be verified. Check https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-118710
Workaround
Unknown. No patch-independent workaround was confirmed by the sources.
Exploitation
- No evidence of exploitation in the wild found.
- No public proof of concept found.
- CISA SSVC: exploitation none, not automatable, total technical impact.
- The CVE record's temporal vector includes E:U (exploit code maturity: unproven).
Our recommendation
- Install the November 2026 Office security updates on all affected Office clients as soon as possible, and verify the fixed build in the MSRC advisory.
- Prioritise staff who open spreadsheets from external senders.
- Check whether Office Online Server is in use.
- Keep email filtering and attachment scanning active, and keep Protected View enabled.
- Monitor for exploitation news and update CVE status when NVD analysis is published.
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
- CVE.org record CVE-2026-118710 www.cve.org
- MSRC Security Update Guide (vendor advisory) msrc.microsoft.com
- Strix CVE-2026-118710 (aggregator, unverified) www.strix.ai
- threatint CVE-2026-118710 (aggregator, unverified) cve.threatint.com
- Patch Tuesday November 2026 roundup cybersecuritynews.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, 21:52.
Original description (NVD)
Use after free 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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