# CVE-2026-66306: Skype for Business Information Disclosure Vulnerability

CVE-2026-66306 is fixed in 3 products on 1 platform, first by KB5123301, released September 8, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-66306
- Priority: Routine
- CVSS: 6.5 (Important)
- EPSS: 0.0092
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Vendor exploitability assessment: Exploitation Less Likely
- Published: Sep 8, 2026
- Weakness: Generation of Error Message Containing Sensitive Information
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-66306

## Description

<p>Generation of error message containing sensitive information in Skype for Business allows an unauthorized attacker to disclose information over a network.</p>

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Microsoft | Skype for Business Server 2015 CU13 |  | [KB5123301](https://patchblox.com/security/data/fix/microsoft/kb5123301.md) | Sep 8, 2026 |
| Microsoft | Skype for Business Server 2019 CU8 |  | [KB5123300](https://patchblox.com/security/data/fix/microsoft/kb5123300.md) | Sep 8, 2026 |
| Microsoft | Skype for Business Server Subscription Edition CU1 |  | [KB5123287](https://patchblox.com/security/data/fix/microsoft/kb5123287.md) | Sep 8, 2026 |

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Data as of 2026-11-08T13:06:02Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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