Retrospective for 2026-08-03, compiled on 27 October 2026. The date identifies the day being analysed; source publication and revision dates are recorded below.
What this advisory changes in your environment
The starting point is CERTFR-2026-AVI-0961, published on 2026-08-03. Its scope includes Office, Microsoft Excel 2016 (édition 32 bits), Microsoft Excel 2016 (édition 64 bits). Reported consequences are remote code execution. These statements apply to the advisory’s scope; they do not assign every consequence to every product or CVE.
This case contains 10 version entries; CVE identifier count: 1. Track remediation by component: a successful overall update does not demonstrate that Office and Microsoft Excel 2016 (édition 64 bits) each received their respective fix.
Products and versions to examine
- Reference
- CERTFR-2026-AVI-0961
- Source first published
- 2026-08-03
- Latest source revision available for this day
- 2026-08-03
- Named components
- Office, Microsoft Excel 2016 (édition 32 bits), Microsoft Excel 2016 (édition 64 bits)
- CVE identifiers
- CVE-2026-62870
| Component | Published condition |
|---|---|
| Microsoft Excel 2016 (édition 32 bits) | < 16.0.5561.1001 |
| Microsoft Excel 2016 (édition 64 bits) | < 16.0.5561.1001 |
For Microsoft Excel 2016 (édition 32 bits), the published condition is “< 16.0.5561.1001”. Compare the version actually loaded with that condition within its own release branch. A fix installed on another edition of Office does not close this case.
Mechanism and prerequisites
Code execution can give an attacker the permissions of the affected process. Check the service account and reachable network destinations. Component isolation can reduce lateral movement opportunities, but does not replace the fix.
For CERTFR-2026-AVI-0961, the retained documents do not provide a suitably dated primary CVE record to establish this case’s prerequisites. Required authentication, user interaction and active exploitation therefore remain unestablished here; they are not inferred from Office or the risk category alone.
Choose the appropriate intervention
- Locate Microsoft Excel 2016 (édition 32 bits) instances, running releases and service owners. Record condition < 16.0.5561.1001 in the ticket alongside reference CERTFR-2026-AVI-0961.
- Compare the installed branch with the vendor’s Microsoft Excel 2016 (édition 32 bits) release notes. Prepare the package for that branch and a dependent-service test, retaining the pre-change state.
- After changing Microsoft Excel 2016 (édition 32 bits), capture the loaded version again and verify the workflow below. Any exception needs an owner, an exposure-reduction measure and an expiry date.
Verify the fix in a real workflow
Validation scenario to adapt for Office: For Microsoft Excel 2016 (édition 32 bits), capture the version loaded by the process or active kernel, then restart only as required by maintenance instructions. Check a dependent workflow and look for embedded copies in distributed images or executables. This is a proposed defensive check, not a claim that testing was performed against third-party systems.
Limit of case CERTFR-2026-AVI-0961: this analysis replaces neither vendor prerequisites nor investigation of your logs. Only documented versions are reproduced; no attack date or victim is invented.
Questions specific to this case
Which condition should be checked for Microsoft Excel 2016 (édition 32 bits)?
Advisory CERTFR-2026-AVI-0961 states: Microsoft Excel 2016 (édition 32 bits) — < 16.0.5561.1001. Check the edition and running release; do not extend the published boundary to branches absent from the advisory.
Why not use one fix for Office and Microsoft Excel 2016 (édition 64 bits)?
CERTFR-2026-AVI-0961 distinguishes these components within a scope containing 10 entries. Match each branch to its own update documentation and functional check.
What is still needed to assess Office exposure?
For Office, establish the running version, the path to the component and process permissions. The sources retained for CERTFR-2026-AVI-0961 do not establish every prerequisite or active exploitation.
Sources and related reading
Practical guide : Prioritize vulnerabilities and verify remediation
Explore the decision addressed in this case
Complete source advisory inventory
The article table may be an extract. These lists contain every affected-system entry and CVE in the specified advisory revision. They are not an inventory of your assets and do not map every CVE to every product.
Official source · CERTFR-2026-AVI-0961
Advisory revision : · Checked on :
Affected systems · 10
Original French wording is retained to avoid ambiguous translations of version conditions.
- Microsoft Office LTSC 2021 pour éditions 64 bits
- Microsoft Office LTSC 2021 pour éditions 32 bits
- Microsoft Office 2019 pour éditions 32 bits
- Microsoft 365 Apps pour Enterprise pour systèmes 64 bits
- Microsoft Office 2019 pour éditions 64 bits
- Microsoft Office LTSC 2024 pour éditions 64 bits
- Microsoft Excel 2016 (édition 32 bits) versions antérieures à 16.0.5561.1001
- Microsoft Excel 2016 (édition 64 bits) versions antérieures à 16.0.5561.1001
- Microsoft Office LTSC 2024 pour éditions 32 bits
- Microsoft 365 Apps pour Enterprise pour systèmes 32 bits