Microsoft Office Excel: Double free leads to remote code execution
Summary
A double free vulnerability (CWE-415) in Microsoft Office Excel allows an unauthorized attacker to execute code over a network. The CNA rates it CVSS 8.8 with high impact on confidentiality, integrity and availability. Exploitation requires that a user interacts with a crafted file, for example one received by email.
Affected
- Microsoft 365 Apps for Enterprise: 16.0.1 before the build listed at https://aka.ms/OfficeSecurityReleases
- Office 365 for Mac: 1.0.0 before 16.115.26110837
- Office LTSC 2021: 16.0.1 before 16.0.14334.21048
- Office LTSC 2024: 16.0.0 before 16.0.17932.21140 (secondary source, not verified)
- Office LTSC for Mac 2021 and 2024: 16.0.1 before 16.115.26110837 (secondary source, not verified)
- Office Online Server: 16.0.0.0 before 16.0.10417.20236 (secondary source, not verified)
Fixed in
Unknown. Builds are listed as fixed in the affected section, but the vendor advisory was not verified.
Workaround
Unknown. No vendor workaround was found.
Exploitation
- No public exploit or proof of concept was found for this CVE.
- CISA SSVC: exploitation none, automatable no, technical impact total.
- The CNA's temporal vector indicates exploit maturity Unproven.
- This CVE is not the Outlook zero-day CVE-2026-124194 in the November 2026 release.
Our recommendation
- Install the Office update for the affected products as part of the regular monthly cycle, prioritising users who open external spreadsheets.
- Verify the exact fixed build in the Microsoft Security Update Guide before rollout.
- Keep Protected View enabled and block macros from the internet.
- Filter or sandbox untrusted Excel attachments.
- Monitor for any change in exploitation status.
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: CVE-2026-118719 msrc.microsoft.com
- CVE Record: CVE-2026-118719 www.cve.org
- Strix AI: CVE-2026-118719 www.strix.ai
- Microsoft November 2026 Patch Tuesday (NT Compatible) www.ntcompatible.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, 21:48.
Original description (NVD)
Double 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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