5.5

CVE-2026-81399: microsoft 365_apps Buffer Over-read

CVSS: 5.5v3.1MediumAnalyzed
Published 08-09-2026Last modified 14-10-2026
Open JSON

Vulnerability summary

CVE-2026-81399 is a medium (CVSS 5.5) Buffer Over-read vulnerability in microsoft 365_apps. EPSS estimates a 0.54% chance of exploitation in the next 30 days, higher than 44.4% of scored vulnerabilities.

Overall risk
22/100
0100
Low · default modelHow is this calculated?
CVSS score
5.5/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.54%
0%100%
Low · +0.16 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 08-09-2026
    PublishedVulnerability first disclosed.
  2. 14-10-2026
    Last modifiedVulnerability information updated.

Description

Buffer over-read in Microsoft Office Excel allows an unauthorized attacker to disclose information locally.

CVSS metrics

2 scores · 2 sources · 1 version

EPSS trend

Probability

0.54%

Chance of exploitation in the next 30 days

Percentile

44%

Versus all other CVEs

30-day change

+0.16 pp

From 0.38% on 20-09-2026

20-09-202620-10-2026
EPSS score
0.54%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Microsoft16 products

1 vendor · 16 products

References

1 links