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CVE-2026-66305
Skype for Business Spoofing Vulnerability
High7.1EPSS 0.53%
- Published
- Updated
- Reserved
- Assigned by
- microsoft
Description
Use of client-side authentication in Skype for Business allows an authorized attacker to perform spoofing over a network.
Timeline
ID reserved
By microsoft
- 46 days later
· 46 days later
Published
- 53 days later
· 53 days later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| microsoftCNA (assigner) | 3.1 | High7.1 | 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 |
| NVDNVD · Analyzed | 3.1 | High7.1 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N |
- EPSS (exploitation in 30 days)
- 0.53% · top 55% of all CVEs (7 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
Loading the EPSS history…
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.1.
Weakness
Affected products
Microsoft · Skype for Business Server 2015 CU13
- affected 9319.0 – < 6.0.9319.885
Microsoft · Skype for Business Server 2019 CU8
- affected 2046.0 – < 7.0.2046.569
Microsoft · Skype for Business Server Subscription Edition CU1
- affected 2046.0 – < 7.0.2046.879
References (1)
- Skype for Business Spoofing Vulnerability (opens in a new tab)vendor-advisorypatch
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-66305)Record last updated .