Windows DNS Server: Information disclosure through out-of-bounds read
Summary
A out-of-bounds read in the Windows DNS Server role allows an authorized attacker with high privileges to read memory over the network and disclose information. The impact is limited to confidentiality, with no integrity or availability impact according to the CVSS vector. Leaked memory could help an attacker chain other flaws, so internal DNS servers should be patched in the regular update cycle.
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 (per CVE record; verify in MSRC advisory)
- Windows client editions: Unknown.
Fixed in
- Windows Server 2016 and Server Core: 10.0.14393.9688 or later
- Windows Server 2019 and Server Core: 10.0.17763.9487 or later
- Windows Server 2022: 10.0.20348.5870 or later
- Windows Server 2025 and Server Core: 10.0.26100.33822 or later (verify in MSRC advisory)
- Released with the November 2026 Patch Tuesday updates (November 10, 2026).
Workaround
Unknown. No vendor workaround identified; patching is the stated fix.
Exploitation
- No evidence of exploitation in the wild found.
- CISA SSVC: exploitation none, not automatable, partial technical impact.
- Rapid7 rates it Exploitation Less Likely; not publicly disclosed.
- No public proof-of-concept found.
Our recommendation
- Apply the November 2026 cumulative update to all Windows Server systems running the DNS Server role, starting with domain controllers.
- Verify the Server 2025 build number against the MSRC advisory.
- Schedule internal DNS servers in the next maintenance window; patch sooner if DNS is reachable from untrusted networks.
- Restrict high-privilege access to DNS servers and monitor for unusual DNS server activity.
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
- MSRC Security Update Guide: CVE-2026-96986 msrc.microsoft.com
- CVE Record: CVE-2026-96986 www.cve.org
- VulDB: CVE-2026-96986 vuldb.com
- Rapid7: Patch Tuesday November 2026 www.rapid7.com
- BleepingComputer: Microsoft November 2026 Patch Tuesday www.bleepingcomputer.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, 19:34.
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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