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Microsoft Windows Error Reporting: Remote code execution (stack buffer overflow)

CVE-2026-83643High 8.8

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Summary

A stack-based buffer overflow in Windows Error Reporting (WER), the Windows component that collects crash data, allows an unauthorized attacker to execute code over a network. The attack requires user interaction, such as opening a crafted file or link, and no privileges. The CVSS base score is 8.8 (high), and the CVE record lists impact on confidentiality, integrity and availability.

Affected

  • Microsoft's CNA record lists these builds as affected: Windows 10 1607 (10.0.14393.0 to below 10.0.14393.9612), Windows 10 1809 (below 10.0.17763.9376), Windows 10 21H2 (below 10.0.19044.7807), Windows 10 22H2 (below 10.0.19045.7807), Windows 11 23H2 (below 10.0.22631.7652), Windows 11 24H2 (below 10.0.26100.9711), Windows 11 25H2 (below 10.0.26200.9711), Windows 11 26H1 (below 10.0.28000.3231), Windows 11 26H2 (below 10.0.26300.9711), Windows Server 2012 and 2012 R2 (see CNA record), and Windows Server 2016 (below 10.0.14393.9612).
  • Note: the CPE in the input (Windows 10 1607) does not match the other secondary data, which points to Windows 11 24H2 / Server 2025 builds. Verify against the MSRC advisory.

Fixed in

  • Fixed in the builds at or above the versions listed under affected, according to the CNA record. Unknown for the exact KB numbers for Windows 10 1607 and Server 2016; the MSRC advisory is the authoritative source.

Workaround

Unknown.

Exploitation

  • CISA SSVC assessment: exploitation none, not automatable, technical impact total.
  • Not listed in the CISA KEV catalog at the time of the research snapshot.
  • EPSS about 0.009 (low).
  • No public proof-of-concept exploit found in the sources reviewed.
  • Vendor exploitation flag not confirmed.

Our recommendation

  • Identify all Windows hosts, especially servers and internet-facing systems, and check their build numbers against the fixed builds in the MSRC advisory.
  • Install the October 2026 cumulative updates, starting with internet-facing servers, RDP and VPN gateways and then workstations.
  • Replace systems that are no longer supported, such as Windows 10 1607 or Server 2016 if they receive no fixes.
  • Monitor the CISA KEV catalog and public exploit sources, as the CVSS is high and exploit code could appear quickly.

Information from Microsoft (Patch Tuesday October 2026)

Severity (Microsoft)
Important
Impact
Remote code execution – Windows Error Reporting
Status on Patch Tuesday
Neither exploited nor publicly disclosed
Exploitability assessment
Exploitation unlikely
Product family
Windows, Windows ESU (Extended Security Updates)
Updates (KB)
KB5126651, KB5126655, KB5126657, KB5126646, KB5127648, KB5126653

Entry in the Microsoft Security Update Guide

Public exploits

PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.

Research sources

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 31 Oct 2026, 18:37.

Original description (NVD)

Stack-based buffer overflow in Windows Error Reporting allows an unauthorized attacker to execute code over a network.

NVD references (1)

Sources

The tracker combines official, freely usable data sources – updated continuously:

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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