CVE-2026-56159 Details
Description
Heap-based buffer overflow in Windows DHCP Server allows an unauthorized attacker to execute code over a network.
A heap-based buffer overflow vulnerability has been identified in the Windows DHCP Server. This vulnerability allows an unauthorized attacker to execute code remotely over the network. The issue arises when the DHCP server is configured to provide data for Option 43.
Users can download the security update for this vulnerability via the Microsoft Update Catalog. Security update KB5099538 is available for Windows Server 2019 and Windows 10 Version 1809. For Windows Server 2012 R2, the security update is included in the monthly rollup for that version. Windows Server 2022 users can also find the security update in the Microsoft Update Catalog.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Jul 11, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-56159 | [email protected] | PatchVendor Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-122 | Heap-based Buffer Overflow | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| microsoft windows 10 1607 | < 10.0.14393.9339 |
CPE
Remediation
| |
| microsoft windows 10 1809 | < 10.0.17763.9020 |
CPE
Remediation
| |
| microsoft windows server 2012 | r2 |
CPE
Remediation
| |
| microsoft windows server 2016 | < 10.0.14393.9339 |
CPE
Remediation
| |
| microsoft windows server 2019 | < 10.0.17763.9020 |
CPE
Remediation
| |
| microsoft windows server 2022 | < 10.0.20348.5386 |
CPE
Remediation
| |
| microsoft windows server 2025 | < 10.0.26100.33158 |
CPE
Remediation
| |
Change History
4 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 21, 2026 | Initial Analysis | [email protected] |
| Jul 15, 2026 | CVE Modified | CISA-ADP |
| Jul 14, 2026 | CVE Modified | CISA-ADP |
| Jul 14, 2026 | New CVE Received | [email protected] |