Microsoft Windows Server 2025 DNS Server: Remote code execution via use-after-free
Summary
A use-after-free flaw in the DNS Server role of Windows Server 2025 allows an unauthenticated attacker on the network to execute code. Microsoft rates the CVSS 3.1 base score at 8.1 with high attack complexity and no privileges or user interaction required. Internal-only DNS servers face lower risk, while DNS servers reachable from the internet are the highest priority.
Affected
- Windows Server 2025 from 10.0.26100.0 before 10.0.26100.33822
- Windows Server 2025 (Server Core installation) from 10.0.26100.0 before 10.0.26100.33822
- Whether older Windows Server releases are affected: Unknown.
Fixed in
- Windows Server 2025 and Server Core: build 10.0.26100.33822 or later (per CVE record and third-party trackers; confirm on the MSRC page).
Workaround
- Unknown. No vendor workaround found.
- Until patched, keep DNS servers off the public internet unless required and restrict which hosts can reach the DNS service.
Exploitation
- No evidence of in-the-wild exploitation found at publication.
- No public proof-of-concept found at publication.
- CISA SSVC: Exploitation none, Automatable no, Technical Impact total.
- Vendor temporal vector E:U (exploit code maturity unproven).
Our recommendation
- Identify all Windows Server 2025 hosts running the DNS Server role, including Server Core.
- Install the cumulative update that brings the build to 10.0.26100.33822 or later, starting with internet-facing DNS servers.
- Confirm the fix and check older Windows Server versions on the MSRC page.
- Monitor NVD, CISA KEV and public PoC sources for changes.
Information from Microsoft (Patch Tuesday November 2026)
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Microsoft Security Update Guide: CVE-2026-96177 msrc.microsoft.com
- CVE Record CVE-2026-96177 www.cve.org
- Zero Day Initiative: November 2026 Security Update Review www.zerodayinitiative.com
- OffSeq Radar: CVE-2026-96177 radar.offseq.com
- Strix: CVE-2026-96177 www.strix.ai
- Patch Tuesday listing (newsbeep) www.newsbeep.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, 01:31.
Original description (NVD)
Use after free in DNS Server allows an unauthorized 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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