CVE-2026-105588: Windows DHCP Server Elevation of Privilege Vulnerability
CVE-2026-105588 is an elevation of privilege vulnerability in Windows DHCP Server, rated Important by Microsoft, with a CVSS 3.1 base score of 6.4 (Medium). An attacker can exploit it by an attacker with local access, with high privileges and without user interaction. Microsoft has not reported exploitation in the wild and rates exploitation as less likely. Microsoft released the fix on 10 November 2026 in the November 2026 Patch Tuesday, delivered through 5 security updates (KB5131291, KB5131085, KB5131090, KB5131080 and more). It affects 8 products in 2 product families (ESU, Windows).
Key facts
- CVE ID
- CVE-2026-105588
- Severity
- Medium CVSS 6.4
- Microsoft severity
- Important
- Impact
- Elevation of Privilege
- Exploited in the wild
- No
- Publicly disclosed
- No
- Exploitation likelihood
- Less Likely
- CISA KEV
- Not listed
- Released
- Last updated
- Patch Tuesday
- November 2026 Patch Tuesday
- Product families
- ESU, Windows
CVSS score and vector
Microsoft scores CVE-2026-105588 at 6.4 (temporal 5.6) using CVSS 3.1. Vector: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
| Metric | Value |
|---|---|
| Attack vector | Local |
| Attack complexity | High |
| Privileges required | High |
| User interaction | None |
| Scope | Unchanged |
| Confidentiality impact | High |
| Integrity impact | High |
| Availability impact | High |
| Exploit code maturity | Unproven |
| Remediation level | Official fix |
| Report confidence | Confirmed |
Description
Missing authentication for critical function in Windows DHCP Server allows an authorized attacker to elevate privileges locally.
Frequently asked questions (Microsoft)
What could an attacker do by exploiting this vulnerability?
An attacker who successfully exploited this vulnerability could change protected registry settings with the permissions of the Network Service account.
According to the CVSS metric, attack complexity is high (AC:H). What does that mean for this vulnerability?
Successful exploitation requires a specially prepared configuration to be processed when the affected service restarts or the system reboots. The attacker must wait for that service-lifecycle event, which is not reliably under their control.
Affected products (8)
ESU
| Product | Security update | Type | Fixed build | Restart |
|---|---|---|---|---|
| Windows Server 2016 | KB5131291 | Security Update | 10.0.14393.9688 | Yes |
| Windows Server 2016 (Server Core installation) | KB5131291 | Security Update | 10.0.14393.9688 | Yes |
Windows
| Product | Security update | Type | Fixed build | Restart |
|---|---|---|---|---|
| Windows Server 2019 | KB5131085 | Security Update | 10.0.17763.9487 | Yes |
| Windows Server 2019 (Server Core installation) | KB5131085 | Security Update | 10.0.17763.9487 | Yes |
| Windows Server 2022 | KB5131090 | Security Update | 10.0.20348.5870 | Yes |
| Windows Server 2022 (Server Core installation) | KB5131090 | Security Update | 10.0.20348.5870 | Yes |
| Windows Server 2025 | KB5131080 KB5131077 | Security Update Security Hotpatch Update | 10.0.26100.33822 10.0.26100.33730 | Yes No |
| Windows Server 2025 (Server Core installation) | KB5131080 KB5131077 | Security Update Security Hotpatch Update | 10.0.26100.33822 10.0.26100.33730 | Yes No |
Security updates (5)
Acknowledgments
Revision history
| Version | Date | Description |
|---|---|---|
| 1.0 | Information published. |