CVE-2026-81399

MEDIUM
Published Sep 8, 2026 Modified Sep 9, 2026 CWE-126

Description

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

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CVSS v3.1 Score

5.5
MEDIUM
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

EPSS — Exploit Prediction

0.0038
Probability of exploitation
0.32%
Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-126 CWE-126

Affected Products

Vendor Product
microsoft 365_apps
microsoft 365_apps
microsoft excel
microsoft excel
microsoft microsoft_365
microsoft office_2016
microsoft office_2016
microsoft office_2019
microsoft office_2019
microsoft office_2021
microsoft office_2021
microsoft office_2021
microsoft office_2024
microsoft office_2024
microsoft office_2024

References

Frequently Asked Questions

What is CVE-2026-81399? +
Buffer over-read in Microsoft Office Excel allows an unauthorized attacker to disclose information locally. It has a CVSS v3.1 base score of 5.5 (MEDIUM).
How severe is CVE-2026-81399? +
CVE-2026-81399 has a CVSS v3.1 score of 5.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0038, placing it in the 0th percentile for exploitation probability.
What products are affected by CVE-2026-81399? +
CVE-2026-81399 affects products from microsoft, specifically: 365_apps, excel, microsoft_365, office_2016, office_2019, office_2021, office_2024. Check the affected products table above for specific version ranges.
How do I check if I'm vulnerable to CVE-2026-81399? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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