# CVE-2026-66307

## Summary

- **CVE ID:** CVE-2026-66307
- **Severity:** HIGH
- **CVSS Score:** 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C)
- **CWE:** CWE-191
- **Published:** Sep 8, 2026
- **Last Modified:** Sep 11, 2026

## Description

Integer underflow (wrap or wraparound) in Skype for Business allows an unauthorized attacker to deny service over a network.

## Affected Products

- Microsoft — Skype for Business Server 2015 CU13 (9319.0)
- Microsoft — Skype for Business Server 2019 CU8 (2046.0)
- Microsoft — Skype for Business Server Subscription Edition CU1 (2046.0)

## References

- [CNA](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-66307)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.65%
- **EPSS Percentile:** 48.9

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-11._