Authenticated service interruption via NULL pointer dereference
Published Sep 8, 2026 · Updated Sep 10, 2026
NULL pointer dereference in Microsoft Skype for Business Server allows remote authenticated users to interrupt service over a network. Microsoft identifies the fault as a NULL pointer dereference but does not disclose the affected server component or the input that reaches it. Exploitation requires low-privileged authentication, needs no user interaction, and can make the service unavailable without reported data disclosure or modification.
Summary
What happened
NULL pointer dereference in Microsoft Skype for Business Server allows remote authenticated users to interrupt service over a network. Microsoft identifies the fault as a NULL pointer dereference but does not disclose the affected server component or the input that reaches it. Exploitation requires low-privileged authentication, needs no user interaction, and can make the service unavailable without reported data disclosure or modification.
The record
- CVE
- CVE-2026-66303
- Published
- Sep 8, 2026
- Updated
- Sep 10, 2026
- Vendor
- Microsoft
- Product
- Skype for Business Server Subscription Edition
- Classifications
- CWE-476, T1499
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Sep 8, 2026CVE publishedPublication date reported by the CVE source.
- Sep 10, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=2046.0 <7.0.2046.879
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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