Skype for Business
CVE-2020-1025 — Microsoft Office Elevation of Privilege Vulnerability
Executive Summary
An elevation of privilege vulnerability exists when Microsoft SharePoint Server and Skype for Business Server improperly handle OAuth token validation. An attacker who successfully exploited the vulnerability could bypass authentication and achieve improper access. To exploit this vulnerability, an attacker would need to modify the token. The update addresses the vulnerability by modifying how Microsoft SharePoint Server and Skype for Business Server validate tokens.
Overview
9.8
CVSS CRITICAL
Critical
MS Severity
Not Exploited
MS Exploit Status
Less Likely
MS Exploit Likelihood
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
ATTACK VECTOR
Network
ATTACK COMPLEXITY
Low
PRIVILEGES REQUIRED
None
USER INTERACTION
None
SCOPE
Unchanged
EPSS Score
0.05853
probability of exploitation in the next 30 days
0.92234 percentile - updated 2026-06-21
View on FIRST.org
Affected Products
6 affected products
| Product | KB Article | Severity | Impact | Restart Required |
|---|---|---|---|---|
| Microsoft Lync Server 2013 | 4571334 (Security Update) |
Critical | Elevation of Privilege | Maybe |
| Microsoft SharePoint Enterprise Server 2016 | 4484436 (Security Update) |
Critical | Elevation of Privilege | Maybe |
| Microsoft SharePoint Foundation 2013 Service Pack 1 | 4484448 (Security Update) |
Critical | Elevation of Privilege | Maybe |
| Microsoft SharePoint Server 2019 | 4484453 (Security Update) |
Critical | Elevation of Privilege | Maybe |
| Skype for Business Server 2015 CU 8 | 4571333 (Security Update) |
Critical | Elevation of Privilege | Maybe |
| Skype for Business Server 2019 CU2 | 4571332 (Security Update) |
Critical | Elevation of Privilege | Maybe |
Patches
6 patches
| Article | Type | Restart |
|---|---|---|
4571334 |
Security Update | Maybe |
4484436 |
Security Update | Maybe |
4484448 |
Security Update | Maybe |
4484453 |
Security Update | Maybe |
4571333 |
Security Update | Maybe |
4571332 |
Security Update | Maybe |
Known Exploits
No known exploits have been linked for this CVE yet. When available, exploit references will be sourced from public repositories and may be unverified, incomplete, or non-functional. Always review code carefully before use in any environment.
Acknowledgments
Justin Hendricks (@script_happens) of Microsoft
References
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