Active Directory Certificate Services: Information disclosure via buffer over-read
Summary
Windows Active Directory Certificate Services (AD CS) contains a buffer over-read. An authorized attacker with network access and low privileges can read sensitive memory contents, which may expose confidential information. The attack is rated high complexity, and Microsoft describes only a confidentiality impact. No exploitation has been reported.
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
Fixed in
- Windows Server 2016: 10.0.14393.9688 or later
- Windows Server 2019: 10.0.17763.9487 or later
- Windows Server 2022: 10.0.20348.5870 or later
- Windows Server 2025: 10.0.26100.33822 or later
Windows 10 and Windows 11: Unknown.
Workaround
Unknown. No vendor workaround was found in the sources. Apply the security update.
Exploitation
- No known exploitation in the sources.
- CISA SSVC: Exploitation none, Automatable no, Technical Impact partial.
- Not publicly disclosed; no public proof of concept found.
Our recommendation
- Install the November 2026 security update on Windows Server 2016, 2019, 2022 and 2025 hosts that run AD CS, prioritising Certificate Authorities reachable from user subnets.
- Verify the fixed build on the MSRC page before patching decisions.
- Restrict certificate template enrollment rights and disable unused enrollment interfaces.
- Monitor AD CS for unusual certificate requests.
Information from Microsoft (Patch Tuesday November 2026)
- Severity (Microsoft)
- Important
- Impact
- Information disclosure – Windows Active Directory Certificate Services
- 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 Update Guide: CVE-2026-95884 msrc.microsoft.com
- CVE.org CNA record CVE-2026-95884 www.cve.org
- Rapid7: Patch Tuesday November 2026 www.rapid7.com
- Senserva: KB5131090 summary senserva.com
- Encryption Consulting: AD CS attacks 2026 www.encryptionconsulting.com
- Cato Networks: Preventing privilege escalation via AD CS www.catonetworks.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, 18:18.
Original description (NVD)
Buffer over-read in Windows Active Directory Certificate Services 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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