Windows DHCP Server: Information disclosure vulnerability
Summary
A flaw in the Windows DHCP Server role of several Windows Server versions exposes sensitive system information to an unauthorized party. An unauthenticated attacker on the network can read this information, but attack complexity is high and the impact is limited to confidentiality. Microsoft has released fixes, and no public exploit is known.
Affected
- Windows Server 2016 (including Server Core): before 10.0.14393.9688
- Windows Server 2019 (including Server Core): before 10.0.17763.9487
- Windows Server 2022: before 10.0.20348.5870
- Windows Server 2025 (including Server Core): before 10.0.26100.33822
- Windows 10 and other builds: Unknown.
Fixed in
- Install the November 2026 security update for each affected version, reaching at least the following builds:
- Windows Server 2016: 10.0.14393.9688
- Windows Server 2019: 10.0.17763.9487
- Windows Server 2022: 10.0.20348.5870
- Windows Server 2025: 10.0.26100.33822
- KB numbers: Unknown in the checked sources. A third-party site names KB5131080 for Windows Server 2025, which must be verified on the MSRC advisory.
Workaround
Unknown. No vendor workaround was found in the checked sources. Check the FAQ and mitigations section of the MSRC advisory.
Exploitation
- Not publicly disclosed (Rapid7 rating: Exploitation Less Likely)
- CISA SSVC: exploitation none, not automatable
- No public proof of concept or in-the-wild exploitation known as of the sources reviewed
Our recommendation
- Patch all Windows DHCP servers, including failover and branch servers, and handle them as one group with other DHCP fixes from the same update batch.
- Restrict which hosts can reach the DHCP service and keep DHCP servers on trusted VLANs.
- Check whether the DHCP role runs on a domain controller or multi-role server and prioritise those systems.
- Monitor DHCP traffic for unusual activity.
Information from Microsoft (Patch Tuesday November 2026)
- Severity (Microsoft)
- Important
- Impact
- Information disclosure – Windows DHCP Server
- Status on Patch Tuesday
- Neither exploited nor publicly disclosed
- Exploitability assessment
- Exploitation less likely
- Product family
- Windows, Windows ESU (Extended Security Updates)
- Updates (KB)
- KB5131291, KB5131085, KB5131090, KB5131080, KB5131077
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Microsoft Security Response Center: CVE-2026-105557 msrc.microsoft.com
- CVE.org record CVE-2026-105557 www.cve.org
- Rapid7: Patch Tuesday November 2026 www.rapid7.com
- Senserva: KB5131080 (third-party, unverified) senserva.com
- Strix: CVE-2026-105557 (third-party aggregator) www.strix.ai
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 11 Nov 2026, 15:32.
Original description (NVD)
Exposure of sensitive system information to an unauthorized control sphere in Windows DHCP Server allows an unauthorized attacker to disclose information over a network.
NVD references (1)
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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