Multiple vulnerabilities in Microsoft Office patched
Free public brief. The indicators, the detections with Splunk SPL already written (plus Elastic and KQL where they apply), and a Slack alert the next time this touches a vendor you run are in the app — free account, no card.
Thirty-one flaws in Microsoft Office and Microsoft 365 allow remote code execution, privilege escalation, and data disclosure.
CERT-FR has published a security advisory documenting 31 vulnerabilities affecting Microsoft Office and Microsoft 365 applications across Windows and mobile platforms, addressed in a June 2026 security bulletin. The vulnerabilities span multiple risk categories: remote code execution, privilege escalation, confidentiality breaches, and security policy bypass. Affected products include Microsoft 365 Apps for Enterprise, Excel 2016, Office 2016, Office 2019, Office LTSC 2021 and 2024, Office for macOS, Office for Android, PowerPoint for Android, Word 2016, and Office Online Server. All versions prior to specific patched builds are vulnerable; the bulletin provides version thresholds for each affected product line.
The advisory names 31 CVEs but provides no detail on attack vectors, exploitation status, or attack context; defenders must consult the individual Microsoft security bulletins to determine exposure and priority for their estate. The breadth of affected products—spanning 32-bit and 64-bit Windows versions, macOS, Android, and server deployments—means most organizations running Microsoft Office require patches. Given the range of impacts including arbitrary code execution, this is a high-priority patching event warranting urgent action.
Mentioned in this report
Detection guidance
Office Application Spawning Script Interpreter or LOLBin
Detects Office applications launching command shells, script hosts or common download/execute LOLBins, a typical sign of exploitation of an Office vulnerability or a malicious document. Auto-generated starting point — validate and tune in your environment before deploying. IOC matches can false-positive on shared infrastructure and decay as adversary infrastructure rotates.
title: Office Application Spawning Script Interpreter or LOLBin
description: Detects Office applications (Word, Excel, PowerPoint, Outlook, Access,
Publisher, Visio, OneNote) spawning shells, script hosts or download/execute LOLBins.
This is the common post-exploitation pattern after client-side exploitation of Office
RCE flaws. It is generic and not tied to a specific CVE.
tags:
- attack.execution
- attack.t1203
logsource:
category: process_creation
product: windows
detection:
selection_parent:
ParentImage|endswith:
- \WINWORD.EXE
- \EXCEL.EXE
- \POWERPNT.EXE
- \OUTLOOK.EXE
- \MSACCESS.EXE
- \MSPUB.EXE
- \VISIO.EXE
- \ONENOTE.EXE
selection_child:
Image|endswith:
- \cmd.exe
- \powershell.exe
- \pwsh.exe
- \wscript.exe
- \cscript.exe
- \mshta.exe
- \regsvr32.exe
- \rundll32.exe
- \certutil.exe
- \bitsadmin.exe
- \msiexec.exe
- \wmic.exe
condition: selection_parent and selection_child
falsepositives:
- Excel or Word macros and add-ins in business workflows that call cmd.exe or PowerShell
- Outlook add-ins or integrations that launch helper scripts
level: high
id: 83a1dba9-0e7a-59f5-b5a6-a820b52f9625
status: experimental
author: Vorant
references:
- https://www.cert.ssi.gouv.fr/avis/CERTFR-2026-AVI-0727
Office Application Spawning Process From User-Writable Path
Detects Office applications launching a child process whose image sits in a user-writable directory such as AppData, Temp, Users\Public or ProgramData, indicating a dropped payload executed after exploitation. Auto-generated starting point — validate and tune in your environment before deploying. IOC matches can false-positive on shared infrastructure and decay as adversary infrastructure rotates.
title: Office Application Spawning Process From User-Writable Path
description: Detects Office applications creating a child process whose executable
resides in a user-writable location (AppData, Temp, Users\Public, ProgramData).
Exploited Office documents often drop and run a payload from these paths.
tags:
- attack.execution
- attack.t1203
logsource:
category: process_creation
product: windows
detection:
selection:
ParentImage|endswith:
- \WINWORD.EXE
- \EXCEL.EXE
- \POWERPNT.EXE
- \OUTLOOK.EXE
- \MSACCESS.EXE
- \MSPUB.EXE
- \VISIO.EXE
Image|contains:
- \AppData\
- \Temp\
- \Users\Public\
- \ProgramData\
filter_known_updaters:
Image|contains:
- \Microsoft\OneDrive\
- \Microsoft\Teams\
condition: selection and not filter_known_updaters
falsepositives:
- Per-user installed Office add-ins or helper tools that launch from AppData
- Outlook opening attachments that are saved to the temp directory and run by the
user
level: high
id: de6a15c4-673e-5e24-bf3d-f70cefa5374a
status: experimental
author: Vorant
references:
- https://www.cert.ssi.gouv.fr/avis/CERTFR-2026-AVI-0727
Behavioural rules are generated from public reporting — validate in your environment before deploying.
Source reporting: https://www.cert.ssi.gouv.fr/avis/CERTFR-2026-AVI-0727
What this brief leaves out
This page is the free tier: the write-up, the severity, the names. In the app the same report carries its extracted indicators, its detections (Splunk SPL already written, plus Elastic and Microsoft KQL where they apply), the actors and CVEs it names as live profiles, and the vendor research on the same campaign — the primary source the news paraphrased, cited and read directly.
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