CVE-2026-66303: CWE-476: NULL Pointer Dereference in Microsoft Skype for Business Server 2015 CU13
Description
Null pointer dereference in Skype for Business allows an authorized attacker to deny service over a network.
CVSS v3.1
Score 6.5medium
Affected software
Microsoft
Skype for Business Server 2015 CU13
Microsoft
Skype for Business Server 2019 CU8
Microsoft
Skype for Business Server Subscription Edition CU1
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability (CVE-2026-66303) involves a null pointer dereference in Microsoft Skype for Business Server 2015 CU13. It can be exploited by an authorized attacker to cause a denial of service condition over the network. The CVSS 3.1 base score is 6.5, reflecting network attack vector, low attack complexity, required privileges, no user interaction, and impact limited to availability. Microsoft has published an official fix for this issue.
Potential Impact
An authorized attacker can exploit this vulnerability to cause a denial of service (DoS) on the affected Skype for Business Server 2015 CU13, potentially disrupting service availability. There is no impact on confidentiality or integrity according to the CVSS vector.
Mitigation Recommendations
An official fix is available from Microsoft. Users should apply the provided patch as detailed in the Microsoft Security Response Center advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-66303 to remediate this vulnerability.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- microsoft
- Date Reserved
- 2026-07-24T18:06:51.294Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- official-fix
- Vendor Advisory Urls
- [{"url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-66303","vendor":"Microsoft"}]
Threat ID: 6aa059e1acd9273b4913b7f2
Added to database: 09/08/2026, 18:54:25 UTC
Last enriched: 10/14/2026, 21:29:20 UTC
Last updated: 10/23/2026, 15:10:14 UTC
Views: 69
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
External Links
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.