CVE-2026-40358: CWE-416: Use After Free in Microsoft Microsoft 365 Apps for Enterprise
Heap-based buffer overflow in Microsoft Office allows an unauthorized attacker to execute code locally.
AI Analysis
Technical Summary
This vulnerability is a use-after-free condition in Microsoft 365 Apps for Enterprise (version 16.0.1) that leads to a heap-based buffer overflow. It enables an unauthorized attacker to execute code locally, impacting confidentiality, integrity, and availability. The CVSS v3.1 base score is 8.4, indicating high severity. Microsoft has published an official fix and manages remediation for this cloud service. The vendor advisory is available at the Microsoft Security Response Center update guide.
Potential Impact
Successful exploitation allows local code execution without privileges or user interaction, resulting in full compromise of confidentiality, integrity, and availability of the affected system. This can lead to unauthorized code execution and potential system takeover.
Mitigation Recommendations
An official fix is available from Microsoft. Since this is a cloud-hosted service, Microsoft manages the remediation server-side. Users and administrators should follow the guidance in the Microsoft advisory to ensure their environments are updated and protected.
CVE-2026-40358: CWE-416: Use After Free in Microsoft Microsoft 365 Apps for Enterprise
Description
Heap-based buffer overflow in Microsoft Office allows an unauthorized attacker to execute code locally.
CVSS v3.1
Score 8.4high
Affected software
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability is a use-after-free condition in Microsoft 365 Apps for Enterprise (version 16.0.1) that leads to a heap-based buffer overflow. It enables an unauthorized attacker to execute code locally, impacting confidentiality, integrity, and availability. The CVSS v3.1 base score is 8.4, indicating high severity. Microsoft has published an official fix and manages remediation for this cloud service. The vendor advisory is available at the Microsoft Security Response Center update guide.
Potential Impact
Successful exploitation allows local code execution without privileges or user interaction, resulting in full compromise of confidentiality, integrity, and availability of the affected system. This can lead to unauthorized code execution and potential system takeover.
Mitigation Recommendations
An official fix is available from Microsoft. Since this is a cloud-hosted service, Microsoft manages the remediation server-side. Users and administrators should follow the guidance in the Microsoft advisory to ensure their environments are updated and protected.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- microsoft
- Date Reserved
- 2026-04-11T23:06:15.614Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- official-fix
- Is Cloud Service
- true
- Vendor Advisory Urls
- [{"url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40358","vendor":"Microsoft"}]
Threat ID: 6a03654ccbff5d861008c81b
Added to database: 05/12/2026, 17:37:16 UTC
Last enriched: 06/19/2026, 17:36:03 UTC
Last updated: 07/31/2026, 19:22:58 UTC
Views: 53
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
External Links
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.