Microsoft Windows: Information disclosure via buffer over-read in Performance Counters
Summary
A buffer over-read in the Windows Performance Counters component allows a local, authorized attacker to read memory contents they should not see. The impact is limited to confidentiality (C:H, no integrity or availability impact). Exploitation requires a valid low-privilege local account and cannot be triggered remotely.
Affected
- Windows 10 Version 1607 (10.0.14393.0 before 10.0.14393.9688)
- Windows 10 Version 1809 (10.0.17763.0 before 10.0.17763.9487)
- Windows 10 Version 21H2 (10.0.19044.0 before 10.0.19044.7846)
- Windows 10 Version 22H2 (10.0.19045.0 before 10.0.19045.7846)
- Windows 11 Version 23H2 (10.0.22631.0 before 10.0.22631.7711)
- Windows 11 Version 24H2 (10.0.26100.0 before 10.0.26100.9974)
- Windows 11 Version 25H2 (10.0.26200.0 before 10.0.26200.9974)
- Windows 11 Version 26H1 (10.0.28000.0 before 10.0.28000.3501)
- Windows 11 Version 26H2 (10.0.26300.0 before 10.0.26300.9974)
- Windows Server 2016, including Server Core (10.0.14393.0 before 10.0.14393.9688)
- Windows Server 2019, including Server Core (10.0.17763.0 before 10.0.17763.9487)
- Windows Server 2022 (10.0.20348.0 before 10.0.20348.5870)
Fixed in
- Fixed in the Windows security updates from November 2026 (Patch Tuesday) for the builds listed above, at the build numbers stated in the affected ranges.
- Exact KB numbers: check Microsoft Update Catalog or Windows release health; the KB number from third-party sources is not verified.
Workaround
Unknown. No vendor-documented workaround is known; installing the security update is the only documented remedy.
Exploitation
- Not known to be exploited in the wild.
- CISA SSVC assessment: exploitation none, not automatable, partial technical impact.
- No public proof of concept found; this reflects a search result, not a confirmed absence.
Our recommendation
- Install the November 2026 Windows security update on all affected systems, prioritising multi-user systems, terminal and RDP servers.
- Check that all systems run a supported Windows version and whether Extended Security Updates apply to older builds (1607, 1809, 21H2, 22H2).
- Restrict local logon to trusted accounts and monitor shared hosts for suspicious local activity.
- Verify the affected versions against the MSRC advisory before rollout.
Information from Microsoft (Patch Tuesday November 2026)
- Severity (Microsoft)
- Important
- Impact
- Information disclosure – Windows Performance Counters
- 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, KB5131096, KB5131090, KB5131087, KB5132061
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Microsoft Security Update Guide: CVE-2026-88220 msrc.microsoft.com
- CVE.org CVE Record: CVE-2026-88220 www.cve.org
- Strix: CVE-2026-88220 (third-party) www.strix.ai
- Senserva KB 5131085 (third-party, unverified) senserva.com
- Patch Tuesday coverage, November 2026 (third-party) www.anoopcnair.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, 16:37.
Original description (NVD)
Buffer over-read in Windows Performance Counters 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.
We check whether your systems are affected, install updates and close the gap – continuously with the System Health Checker if you wish.