Microsoft Office Outlook: Information disclosure through out-of-bounds read
Summary
Microsoft Office Outlook contains an out-of-bounds read vulnerability (CWE-125) that allows an attacker to disclose information. According to the CVSS vector, the attack needs no privileges and no user interaction over the network, and it affects confidentiality only. No exploitation in the wild is known, and CISA SSVC rates exploitation as none.
Affected
- Microsoft 365 Apps for Enterprise (16.0.1 up to the fixed build, exact range unknown)
- Office 365 for Mac (before 16.114.26101123)
- Office LTSC 2021 (before 16.0.14334.20974)
- Office LTSC 2024 (before 16.0.17932.21056)
- Office LTSC for Mac 2021 and 2024 (before 16.114.26101123)
Fixed in
- Office LTSC 2021: 16.0.14334.20974 or later
- Office LTSC 2024: 16.0.17932.21056 or later
- Office for Mac and Office LTSC for Mac: 16.114.26101123 or later (per CVE record)
- Microsoft 365 Apps for Enterprise: Unknown; check the MSRC advisory for the build
Workaround
Unknown. No vendor-documented workaround is known; install the update.
Exploitation
- No evidence of exploitation in the wild.
- Not listed in the CISA KEV catalog.
- No public proof of concept found.
- EPSS score about 1.1%.
Our recommendation
- Install the October 2026 Office security updates on all Outlook clients through the normal update channels.
- Confirm that Office LTSC 2021 installs received the update. Office 2021 no longer receives updates from October 13, 2026, so plan an upgrade if they did not.
- Verify the fixed build for Microsoft 365 Apps against the MSRC advisory before rollout.
- Monitor for abnormal Outlook behaviour and review exposure of mail clients in mail-heavy environments.
Information from Microsoft (Patch Tuesday October 2026)
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Microsoft Security Update Guide: CVE-2026-70281 msrc.microsoft.com
- Microsoft 365 Apps security updates learn.microsoft.com
- Microsoft 365 Apps update history by date learn.microsoft.com
- OpenCVE: CVE-2026-70281 app.opencve.io
- VULNERS: NVD CVE-2026-70281 vulners.com
- Microsoft Outlook (Wikipedia) en.wikipedia.org
- Office Watch: October 2026 Office changes office-watch.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 2 Nov 2026, 18:55.
Original description (NVD)
Out-of-bounds read in Microsoft Office Outlook 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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