High severity · published Oct 13, 2026
CVE-2026-70257
Microsoft Office Outlook Remote Code Execution Vulnerability
8.8
CVSS
0.9%
EPSS
No
On KEV
Description
Heap-based buffer overflow in Microsoft Office Outlook allows an unauthorized attacker to execute code over a network.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.9% · higher than 60% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
OF
Office · Microsoft
All versions, or not specified · source: NVD
M3
Microsoft 365 Apps for Enterprise · Microsoft
16.0.1 before https://aka.ms/OfficeSecurityReleases · source: vendor
MO
Microsoft Office LTSC 2021 · Microsoft
16.0.1 before 16.0.14334.20974 · source: vendor
MO
Microsoft Office LTSC 2024 · Microsoft
16.0.0 before 16.0.17932.21056 · source: vendor
O2
Office 2021 · Microsoft
All versions, or not specified · source: NVD
O2
Office 2024 · Microsoft
All versions, or not specified · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-70257
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-70257
vendor-advisory
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-70257
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