CVE-2026-85873ImportantEoPNetwork

Skype for Business Elevation of Privilege Vulnerability

MSRC advisory NVD CVE.org

Assessment

Improper authorization in Skype for Business and Microsoft Lync allows an authorized attacker to elevate privileges over a network.

Severity: Important
CVSS base score: 6.5CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C
Impact: Elevation of Privilege
EPSS, next 30 days: Not scored yet
Public exploit code: No Nuclei template lists it
Exploitability: Exploitation Less Likely
Publicly disclosed: No
Customer action: Required: apply the update
Component: Skype for Business and Microsoft Lync
Weakness: CWE-639: Authorization Bypass Through User-Controlled Key
Issued by: Microsoft
Published: 13 Oct 2026 · October 2026
Last revised: 13 Oct 2026

CVSS 3.1 base metricsRed raises the risk · green lowers it

Attack vector: NetworkAV:N
Attack complexity: LowAC:L
Privileges required: LowPR:L
User interaction: NoneUI:N
Scope: UnchangedS:U
Confidentiality: HighC:H
Integrity: NoneI:N
Availability: NoneA:N

Updates that fix it

3 KBs

KB	Type	Applies to	Other CVEs
KB5131692	Security Update	Skype for Business Server Subscription Edition CU1	All CVEs in KB5131692
KB5131693	Security Update	Skype for Business Server 2019 CU8	All CVEs in KB5131693
KB5132779	Security Update	Skype for Business Server 2015 CU13	All CVEs in KB5132779

Affected products

Microsoft Office, Other

4 affected products

Skype for Business Server 2015 CU13
Skype for Business Server 2019 CU8
Skype for Business Server Subscription Edition CU1
Skype for Business Server Subscription Edition RTM

What changed

First observed 14 Oct 2026

No field changes in the recorded history.

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