Windows Error Reporting: Heap-based buffer overflow enables local privilege escalation
Summary
Microsoft Windows Error Reporting, the built-in crash-reporting component, contains a heap-based buffer overflow (CWE-122). An attacker with an existing low-privileged local logon can exploit it to gain higher privileges, with high impact on confidentiality, integrity and availability. The attack is local only and is not reachable from the internet.
Affected
- Windows 10 Version 1607 (builds before 10.0.14393.9612)
- Windows 10 Version 1809 (builds before 10.0.17763.9376)
- Windows 10 Version 21H2 (builds before 10.0.19044.7807)
- Windows 10 Version 22H2 (builds before 10.0.19045.7807)
- Windows 11 Version 23H2 (builds before 10.0.22631.7652)
- Windows 11 Version 24H2 (builds before 10.0.26100.9711)
- Windows 11 Version 25H2 (builds before 10.0.26200.9711)
- Windows 11 Version 26H1 (builds before 10.0.28000.3231)
- Windows 11 Version 26H2 (builds before 10.0.26300.9711)
- Windows Server 2012 and Server Core (builds before 6.2.9200.26434)
- Windows Server 2012 R2 and Server Core (builds before 6.3.9600.23470)
- Windows Server 2016 (builds before 10.0.14393.9612)
Fixed in
- Windows 10 1607 and Windows Server 2016: build 10.0.14393.9612 (KB5126868, released 2026-10-13, per Microsoft release health)
- Other versions: first fixed builds as listed under affected, according to the CVE record. Verify on the MSRC advisory before rollout.
Workaround
Unknown. Microsoft has not published a workaround in the sources reviewed. One aggregator suggests restricting or disabling the Windows Error Reporting service, but this is not Microsoft guidance and was not verified.
Exploitation
- CISA SSVC: exploitation none, not automatable, total technical impact.
- No in-the-wild exploitation known as of the research.
- No public proof of concept found.
- EPSS 0.00318 (very low).
- Vendor-side exploitation status could not be confirmed.
Our recommendation
- Inventory all Windows devices and identify builds below the fixed versions listed above.
- Install the security update (KB5126868 for 1607 and Server 2016) as soon as possible.
- Prioritise devices with shared or untrusted local users, such as kiosks, POS, HMI and shared terminals.
- Windows 10 1607 has reached end of servicing and will not receive future protections. Plan migration to a supported version, for example Windows 11 Enterprise LTSC 2024, or consider Extended Security Updates as a bridge.
- Check the MSRC advisory for the authoritative version list before deployment.
Information from Microsoft (Patch Tuesday October 2026)
- Severity (Microsoft)
- Important
- Impact
- Elevation of privilege – Windows Error Reporting
- Status on Patch Tuesday
- Neither exploited nor publicly disclosed
- Exploitability assessment
- Exploitation less likely
- Product family
- Windows, Windows ESU (Extended Security Updates)
- Updates (KB)
- KB5126651, KB5126655, KB5126657, KB5126646, KB5127648, KB5126653
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Microsoft Security Update Guide: CVE-2026-85800 msrc.microsoft.com
- Microsoft Learn: Windows 10 1607 and Windows Server 2016 release health learn.microsoft.com
- Vulners: CVE-2026-85800 vulners.com
- Vulners: MSCVE MS:CVE-2026-85800 vulners.com
- Strix: CVE-2026-85800 www.strix.ai
- 4sysops: Windows 10 LTSB 2016 end of support and ESU 4sysops.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 2 Nov 2026, 02:12.
Original description (NVD)
Heap-based buffer overflow in Windows Error Reporting allows an authorized attacker to elevate privileges 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.
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