Windows DNS: Information disclosure through out-of-bounds read
Summary
A out-of-bounds read in the Windows DNS Server component allows an attacker with network access to disclose information. The attacker needs high privileges, and the impact is limited to confidentiality, with no integrity or availability impact. Internal DNS servers, often on domain controllers, are normally not reachable from the internet, so exposure is mainly a concern for DNS servers that answer queries from outside.
Affected
- Windows Server 2016 and Server Core installation: before 10.0.14393.9688
- Windows Server 2019 and Server Core installation: before 10.0.17763.9487
- Windows Server 2022: before 10.0.20348.5870
- Windows Server 2025 and Server Core installation: before 10.0.26100.33822 (listed in the CVE record; verify on the MSRC page)
Fixed in
Install the November 2026 security update for the affected Windows Server version. Patched builds: 10.0.14393.9688 (Server 2016), 10.0.17763.9487 (Server 2019), 10.0.20348.5870 (Server 2022), 10.0.26100.33822 (Server 2025).
Workaround
- No vendor workaround known. Unknown.
- Third-party advice (not from Microsoft): IDS signatures for malformed DNS traffic and review of DNS logs.
Exploitation
- CISA SSVC: exploitation none, not automatable.
- Rapid7: exploitation less likely; no public disclosure.
- No public proof of concept and no in-the-wild exploitation known at the time of research.
- The CVSS vector marks exploit code maturity as unproven (E:U).
Our recommendation
- Install the November 2026 cumulative update on all affected Windows Server hosts, prioritising DNS servers.
- Check whether Windows DNS servers are reachable from the internet and restrict access if not required.
- Check whether older Server 2016 or 2019 hosts are covered by Extended Security Updates, as Rapid7 lists this CVE under ESU vulnerabilities.
- Review DNS logs for unusual or malformed queries.
- Recheck NVD once the analysis is complete.
Information from Microsoft (Patch Tuesday November 2026)
- Severity (Microsoft)
- Important
- Impact
- Information disclosure – Windows DNS
- 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-2026-96980 msrc.microsoft.com
- VulDB: CVE-2026-96980 vuldb.com
- Rapid7: Patch Tuesday November 2026 www.rapid7.com
- OffSeq Radar: CVE-2026-96980 radar.offseq.com
- Strix: CVE-2026-96980 www.strix.ai
- gbhackers: Microsoft November 2026 Patch Tuesday gbhackers.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 11 Nov 2026, 19:35.
Original description (NVD)
Out-of-bounds read in Windows DNS allows an authorized 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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