Microsoft Windows: Information disclosure via AMD Zen processor optimization
Summary
Windows versions for clients and servers are affected by a processor optimization flaw in AMD Zen CPUs (CWE-1037). A local attacker with low privileges can read sensitive information from the system, with impact on confidentiality only. User interaction is not required and the flaw is not remotely exploitable.
Affected
- Windows 10 Version 1809 before 10.0.17763.9376
- Windows 11 Version 23H2 before 10.0.22631.7652
- Windows 11 Version 24H2 before 10.0.26100.9711
- Windows 11 Version 25H2 before 10.0.26200.9711
- Windows 11 Version 26H1 before 10.0.28000.3231
- Windows 11 Version 26H2 before 10.0.26300.9711
- Windows Server 2019 (including Server Core) before 10.0.17763.9376
- Windows Server 2022 before 10.0.20348.5761
- Windows Server 2025 (including Server Core) before 10.0.26100.33650
Fixed in
Security update published by Microsoft for the November 2026 Patch Tuesday, for the builds listed above. Verify exact KB numbers in the MSRC update guide, as they could not be confirmed from the vendor source.
Workaround
Unknown. No Microsoft-published workaround was found.
Exploitation
- Microsoft: Exploited: No, Publicly disclosed: No, Exploitation less likely.
- CISA SSVC: Exploitation none, Automatable no, Technical impact partial.
- No public proof of concept or exploit code known.
Our recommendation
- Install the November 2026 Windows security update on all affected clients and servers, following the normal Patch Tuesday cycle.
- Prioritize multi-user systems such as Remote Desktop or terminal servers, shared hosts and virtualisation hosts, where untrusted users or code may run locally.
- Verify the installed build numbers against the MSRC table.
- Monitor the NVD and MSRC entry for updates to the analysis or exploitation status.
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-2026-84005 msrc.microsoft.com
- CVE Record CVE-2026-84005 www.cve.org
- OffSeq Threat Radar: CVE-2026-84005 radar.offseq.com
- Strix: CVE-2026-84005 www.strix.ai
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, 16:40.
Original description (NVD)
Processor optimization removal or modification of security-critical code in AMD Zen allows an authorized attacker to disclose information locally.
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.
Affected? We can help.
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