CVE-2026-62799ImportantRevised 11 Sep
Windows SMB Client Elevation of Privilege Vulnerability
Assessment
Heap-based buffer overflow in Windows SMB Client allows an authorized attacker to elevate privileges locally.
- Severity
- Important
- CVSS base score
- 7.8CVSS:3.1/
AV:L/ AC:L/ PR:L/ UI:N/ S:U/ C:H/ I:H/ A:H/ E:U/ RL:O/ RC:C - Impact
- Elevation of Privilege
- EPSS, next 30 days
- 0.3%Higher than 24% of scored CVEs · FIRST model run 26 Sep 2026 · about EPSS
- Exploitability
- Exploitation Less Likely
- Publicly disclosed
- No
- Customer action
- Required: apply the update
- Component
- Windows SMB Client
- Weakness
- CWE-122: Heap-based Buffer Overflow
- Issued by
- Microsoft
- Published
- 11 Aug 2026 · August 2026
- Last revised
- 11 Sep 2026Updated an acknowledgement. This is an informational change only.
Updates that fix it
1 KB| KB | Type | Restart | Applies to | Other CVEs |
|---|---|---|---|---|
| KB5121000 | Security Update | Required | Windows 11 Version 26H1 for ARM64-based Systems, Windows 11 version 26H1 for x64-based Systems | All CVEs in KB5121000 |
Affected products
Windows2 affected products
- Windows 11 Version 26H1 for ARM64-based Systems
- Windows 11 version 26H1 for x64-based Systems