Microsoft Windows DNS Server: Heap-based buffer overflow leading to remote code execution
Summary
A heap-based buffer overflow in the Windows DNS Server role allows an authorized attacker to execute code over the network. According to the NVD description, the attacker needs some authenticated access (the CVSS vector lists PR:L), but the official advisory has not yet been verified. Servers with the DNS Server role, including domain controllers, are particularly relevant because a successful attack could fully compromise them.
Affected
- Windows Server 2016 (including Server Core): 10.0.14393.0 to before 10.0.14393.9688
- Windows Server 2019 (including Server Core): 10.0.17763.0 to before 10.0.17763.9487
- Windows Server 2022: 10.0.20348.0 to before 10.0.20348.5870
- Windows Server 2025 (including Server Core): 10.0.26100.0 to before 10.0.26100.33822
- Windows Server 2008 R2, 2012 and 2012 R2: Unknown.
Fixed in
- Build numbers from the official CVE record: 10.0.14393.9688 (Server 2016), 10.0.17763.9487 (Server 2019), 10.0.20348.5870 (Server 2022), 10.0.26100.33822 (Server 2025).
- KB numbers: Unknown. Check the MSRC advisory.
Workaround
Unknown. Restricting inbound access to DNS servers to trusted IP ranges is a stopgap only, not a substitute for patching; it has not been confirmed by the vendor advisory.
Exploitation
Unknown. No reports of active exploitation or public proof of concept were found at the time of writing.
Our recommendation
- Retrieve the MSRC advisory and record the affected builds and KB numbers.
- Inventory all servers with the DNS Server role, including domain controllers, internet-facing and branch-office DNS servers.
- Patch in the next maintenance window; check legacy systems for Extended Security Updates coverage.
- Restrict access to DNS servers to trusted networks until patched.
- Recheck the NVD status in a few days, as details may change.
Information from Microsoft (Patch Tuesday November 2026)
- Severity (Microsoft)
- Important
- Impact
- Remote code execution – Role: DNS 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-2026-96002 msrc.microsoft.com
- Zero Day Initiative: October 2026 Security Update Review www.zerodayinitiative.com
- 0patch: legacy Windows Server DNS shielded from CVE-2026-62878 windowsforum.com
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 10 Nov 2026, 20:53.
Original description (NVD)
Heap-based buffer overflow in DNS Server allows an authorized attacker to execute code 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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