Windows: Use-after-free in Internet Explorer allows local privilege escalation
Summary
A use-after-free flaw (CWE-416) in the Internet Explorer component of Windows allows an authorized local user to elevate privileges. The attacker needs a low-privileged logon and high attack complexity applies, but no user interaction is required. The CVSS score is 7.8 (High), and the impact on confidentiality, integrity and availability is rated high.
Affected
- Windows 10 Version 1809 and Windows Server 2019 (incl. Server Core): below 10.0.17763.9376
- Windows 10 Version 21H2: below 10.0.19044.7807
- Windows 10 Version 22H2: below 10.0.19045.7807
- Windows 11 Version 23H2: below 10.0.22631.7652
- Windows 11 Version 24H2: below 10.0.26100.9711
- Windows 11 Version 25H2: below 10.0.26200.9711
- Windows 11 Version 26H1: below 10.0.28000.3231
- Windows 11 Version 26H2: below 10.0.26300.9711
- Windows Server 2022: below 10.0.20348.5761
- Windows Server 2025 (incl. Server Core): below 10.0.26100.33650
Fixed in
- October 2026 security update for the respective build (Windows 10 1809 and Server 2019: KB5126651 according to Tenable)
- Check the MSRC advisory for the KB number of each other build
Workaround
Unknown. No vendor-documented workaround was found.
Exploitation
- Not listed in CISA's KEV catalog
- CISA SSVC: exploitation none, not automatable, technical impact total
- EPSS about 0.27% (as of 31 Oct 2026)
- No public proof of concept found in the research (absence is not proof)
Our recommendation
- Install the October 2026 security update on all affected Windows clients and servers, prioritising Windows 10 1809 and Server 2019
- Check whether any legacy application still depends on Internet Explorer before patching
- Until patched, restrict local logon to trusted users and monitor endpoints for suspicious local privilege escalation
- Monitor the MSRC advisory and CISA KEV for changes in exploitation status
Information from Microsoft (Patch Tuesday October 2026)
- Severity (Microsoft)
- Important
- Impact
- Elevation of privilege – Internet Explorer
- 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-2026-83741 msrc.microsoft.com
- Vulners CVE List entry (CNA data, product list) vulners.com
- Tenable plugin listing www.tenable.com
- OpenCVE CVE-2026-83741 app.opencve.io
- Vulners NVD entry (Tenable plugin reference) vulners.com
- Strix CVE-2026-83741 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 2 Nov 2026, 03:11.
Original description (NVD)
Use after free in Internet Explorer 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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