# CVE-2026-66302: Skype for Business Remote Code Execution Vulnerability CVE-2026-66302 is fixed in 3 products on 1 platform, first by KB5123301, released September 8, 2026. It is not reported as exploited. Patch Radar priority: Urgent. - Web page: https://patchblox.com/security/cve/CVE-2026-66302 - Priority: Urgent - CVSS: 9.8 (Critical) - EPSS: 0.0097 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Vendor exploitability assessment: Exploitation Less Likely - Published: Sep 8, 2026 - Weakness: External Control of File Name or Path - Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-66302 ## Description

External control of file name or path in Skype for Business allows an unauthorized attacker to execute code over a network.

## 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 | | [KB5123287](https://patchblox.com/security/data/fix/microsoft/kb5123287.md) | Sep 8, 2026 | | Microsoft | Skype for Business Server Subscription Edition CU1 | | [KB5123300](https://patchblox.com/security/data/fix/microsoft/kb5123300.md) | Sep 8, 2026 | --- 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo Free to use with attribution: show "Data: Patchblox Patch Radar" with a link to https://patchblox.com/security/patch-radar. Terms, including what needs a written agreement: https://patchblox.com/security/patch-radar/use-the-data Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.