Microsoft Office Outlook Remote Code Execution Vulnerability

published 2026-09-25 44 d ago modified 2026-10-30 9 d ago also EUVD-2026-87317

cvss: 7.5; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.5%; EPSS 0.5% chance of exploitation in 30 days, percentile 39%
public exploits: 0; none known

Integer overflow or wraparound in Microsoft Office Outlook allows an unauthorized attacker to execute code over a network.

Patch / fix

links 1

msrc.microsoft.com/update-guide/vulnerability/CVE-2026-100208 advisory

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: total
Assessed: 45 d ago (2026-09-25)

Exploit prediction

0.45% chance of exploitation in the next 30 days, higher than 39% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	7.5	CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
CNA	3.1	7.5	CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
NVD	3.1	8.1	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

Microsoft Microsoft 365 Apps for Enterprise
Microsoft Microsoft Office LTSC 2021
Microsoft Microsoft Office LTSC 2024

Classification

Weakness

CWE-190 Integer Overflow or Wraparound
CWE-122 Heap-based Buffer Overflow

References

msrc.microsoft.com /update-guide/vulnerability/CVE-2026-100208
vendor-advisory, patch

Sources

CVE List CVE-2026-100208
NVD CVE-2026-100208

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary