Microsoft Office: Buffer over-read leads to information disclosure
Summary
Microsoft Office contains a buffer over-read vulnerability that allows an unauthorized attacker to disclose information over a network. A successful attacker could potentially read small portions of heap memory. Exploitation requires that a victim opens or interacts with a malicious file, such as a document delivered by email or file sharing. Confidentiality is the only affected property.
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 to before 16.115.26110837
- Office LTSC 2021: 16.0.1 to before 16.0.14334.21048
- Office LTSC 2024: 16.0.0 to before 16.0.17932.21140 (unverified)
- Office LTSC for Mac 2021 and 2024: before 16.115.26110837 (unverified)
Fixed in
- Office LTSC 2021: 16.0.14334.21048 (CVE record)
- Office 365 for Mac: 16.115.26110837 (CVE record)
- Microsoft 365 Apps for Enterprise: Unknown build, see https://aka.ms/OfficeSecurityReleases
- Office LTSC 2024 and LTSC for Mac: stated in one third-party source only, to be verified on MSRC
Workaround
- No vendor workaround or documented mitigation known.
- Installing the November 2026 Office security updates is the fix.
Exploitation
- No exploitation in the wild known.
- No public proof-of-concept code known.
- Rapid7 lists exploitation as less likely and not publicly disclosed.
- CISA SSVC: exploitation none, not automatable.
Our recommendation
- Install the November 2026 security updates for all Office installations, including M365 Apps, LTSC and Mac versions.
- Keep Microsoft 365 Apps on a current update channel.
- Verify exact fixed builds on the MSRC advisory before finalizing patch status.
- Remind staff to be cautious with unexpected email attachments and shared files.
- Priority: medium. Heap memory disclosure can help attackers chain other flaws.
Information from Microsoft (Patch Tuesday November 2026)
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Microsoft Security Update Guide: CVE-2026-111293 msrc.microsoft.com
- CVE Record: CVE-2026-111293 www.cve.org
- Rapid7: November 2026 Patch Tuesday www.rapid7.com
- BleepingComputer: November 2026 Patch Tuesday www.bleepingcomputer.com
- CrowdStrike: Patch Tuesday analysis November 2026 www.crowdstrike.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 11 Nov 2026, 12:32.
Original description (NVD)
Buffer over-read in Microsoft Office allows an unauthorized attacker to disclose information 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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