What is CVE-2025-59245?

CVE-2025-59245 is a critical-severity vulnerability in Microsoft Sharepoint Online, classified under Deserialization of Untrusted Data. CVSS score: 9.8/10. Published 2025-11-20.

How severe is CVE-2025-59245?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Deserialization in Microsoft Sharepoint Online

CVE-2025-59245

Microsoft SharePoint Online Elevation of Privilege Vulnerability

Vulnerability class: Insecure Deserialization

Published 2025-11-20 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.011 (63.0th percentile), scored 2026-09-23.

Low probability of exploitation in the next 30 days, but still tracked. 63rd percentile — 63.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.011 · newest: 0.011 · change: 0.000

Affected products

Weakness classification (CWE)

CWE-502 — Deserialization of Untrusted Data

References

msrc.microsoft.com/update-guide/vulnerability/CVE-2025-59245 (vendor-advisory, patch, Vendor Advisory)

Frequently asked questions

What is CVE-2025-59245?: CVE-2025-59245 is a critical-severity vulnerability in Microsoft Sharepoint Online, classified under Deserialization of Untrusted Data. CVSS score: 9.8/10. Published 2025-11-20.
How severe is CVE-2025-59245?: Critical severity. CVSS v3 base score is 9.8 out of 10.