Microsoft Office Spoofing Vulnerability

published 2026-09-08 2 mo ago modified 2026-10-31 8 d ago also EUVD-2026-73643

cvss: 6.5; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.9%; EPSS 0.9% chance of exploitation in 30 days, percentile 59%
public exploits: 0; none known

Insufficiently protected credentials in Microsoft Office allows an unauthorized attacker to perform spoofing over a network.

Patch / fix

links 1

msrc.microsoft.com/update-guide/vulnerability/CVE-2026-64918 advisory

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 1 mo ago (2026-09-09)

Exploit prediction

0.87% chance of exploitation in the next 30 days, higher than 59% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	6.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C
CNA	3.1	6.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

Affected products

Microsoft Microsoft 365 Apps for Enterprise

Classification

Weakness

CWE-522 Insufficiently Protected Credentials

References

msrc.microsoft.com /update-guide/vulnerability/CVE-2026-64918
vendor-advisory, patch

Sources

CVE List CVE-2026-64918
NVD CVE-2026-64918

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