Microsoft Office Outlook: Path traversal leading to remote code execution
Summary
Microsoft Outlook, part of Microsoft 365 Apps for Enterprise and Office LTSC 2021 and 2024, contains a path traversal flaw (CWE-22) that allows code execution over a network. An attacker needs some valid access, such as a mailbox or a low-privileged account, which an authorized attacker or a compromised user could provide. CVSS 3.1 rates it 8.8 (High), but the vector states that no user interaction is required. The flaw is not known to be exploited.
Affected
- Microsoft 365 Apps for Enterprise: 16.0.1 up to the fixed build, which is not given as a build number in the source (see MSRC)
- Office LTSC 2021: 16.0.1 up to but excluding 16.0.14334.21048
- Office LTSC 2024: 16.0.0 up to but excluding 16.0.17932.21140
- Unknown: older Click-to-Run channels and Mac builds
Fixed in
- Fixes published with the November 2026 Microsoft security updates (Patch Tuesday)
- Office LTSC 2021: 16.0.14334.21048 or later
- Office LTSC 2024: 16.0.17932.21140 or later
- Microsoft 365 Apps for Enterprise: Unknown (fixed build not given in the sources; see MSRC)
Workaround
Unknown. No vendor workaround is documented in the sources reviewed; rely on patching.
Exploitation
- Not known to be exploited at the time of writing
- Not listed in CISA KEV
- No public proof-of-concept exploit found
- Do not confuse with the actively exploited Outlook zero-day in the same release (different CVE, NTLM hash leak)
Our recommendation
- Install the November 2026 Office security updates on all Outlook and Microsoft 365 clients
- Verify installed build numbers against the MSRC advisory, especially for Microsoft 365 Apps
- Limit mailbox and low-privileged account access where possible and monitor for unusual Outlook activity
- Watch for NVD enrichment and changes to the exploitation status
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-2026-124228 msrc.microsoft.com
- Strix: CVE-2026-124228 (CNA data copy) www.strix.ai
- Cybersecurity News: Microsoft November 2026 Patch Tuesday cybersecuritynews.com
- BleepingComputer: Microsoft November 2026 Patch Tuesday www.bleepingcomputer.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 10 Nov 2026, 21:06.
Original description (NVD)
Improper limitation of a pathname to a restricted directory ('path traversal') in Microsoft Office Outlook allows an authorized attacker to execute code 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.
Affected? We can help.
We check whether your systems are affected, install updates and close the gap – continuously with the System Health Checker if you wish.