CVE-2026-66305 json
Skype for Business Spoofing Vulnerability
published 2mo ago modified yesterday also EUVD-2026-73937
- cvss
- 7.1
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.5%
- EPSS 0.5% chance of exploitation in 30 days, percentile 45%
- public exploits
- 0
- none known
Summary
Use of client-side authentication in Skype for Business allows an authorized attacker to perform spoofing over a network.
Patch / fix
- Microsoft Skype for Business Server 2015 CU13 6.0.9319.885
- Microsoft Skype for Business Server 2019 CU8 7.0.2046.569
- Microsoft Skype for Business Server Subscription Edition CU1 7.0.2046.879
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Check with FencerCISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 2mo ago
Exploit prediction
0.53% chance of exploitation in the next 30 days, higher than 45% of all scored CVEs (FIRST EPSS, 2026-11-11).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 7.1 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N/E:U/RL:O/RC:C |
| CNA | 3.1 | 7.1 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N |
Affected products
- Microsoft Skype for Business Server 2015 CU13
- Microsoft Skype for Business Server 2019 CU8
- Microsoft Skype for Business Server Subscription Edition CU1
Classification
- Weakness
-
- CWE-603 Use of Client-Side Authentication
References
-
msrc.microsoft.com
/update-guide/vulnerability/CVE-2026-66305
vendor-advisory, patch
Sources
- CVE List CVE-2026-66305
- NVD CVE-2026-66305
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