CVE-2026-66307

HIGH

MEDIUM Priority: 0.09 BB Relevance: 75/100

Published: 2026-09-08 Modified: 2026-10-30 First seen: 2026-10-30 Status: active

Network Low Complexity No Auth No Interaction

AV: Network

AC: Low

PR: None

UI: None

S: Unchanged

C: None

I: None

A: High

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

Vendor	Product	Version
Microsoft	Skype for Business Server 2015 CU13	9319.0 < 6.0.9319.885
Microsoft	Skype for Business Server 2019 CU8	2046.0 < 7.0.2046.569
Microsoft	Skype for Business Server Subscription Edition CU1	2046.0 < 7.0.2046.879

vendor-advisory patch

75 / 100

✓ Network accessible
✓ No authentication
✓ Low complexity
✓ No user interaction

7.5 / 10.0 v3.1

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

1.17%

Raw Score 0.011740

Percentile 67.5%

Date 2026-10-30

mitre ref →