Windows Task Scheduler: Heap-based buffer overflow allows local privilege escalation
Summary
A heap-based buffer overflow in the Windows Task Scheduler component allows an authorized local user with low privileges to elevate their privileges to a higher level. The attacker needs local code execution, so this is a follow-on step after an initial compromise, for example through phishing or a stolen credential. The Microsoft CNA record lists multiple Windows 10, Windows 11 and Windows Server versions. NVD analysis is pending, so the CVSS score may change.
Affected
- Windows 10 Version 1607 (builds before 10.0.14393.9688)
- Windows 10 Version 1809 (builds before 10.0.17763.9487)
- Windows 10 Version 21H2 (builds before 10.0.19044.7846)
- Windows 10 Version 22H2 (builds before 10.0.19045.7846)
- Windows 11 Version 23H2 (builds before 10.0.22631.7711)
- Windows 11 Version 24H2 (builds before 10.0.26100.9974)
- Windows 11 Version 25H2 (builds before 10.0.26200.9974)
- Windows 11 Version 26H1 (builds before 10.0.28000.3501)
- Windows 11 Version 26H2 (builds before 10.0.26300.9974)
- Windows Server 2016 incl. Server Core (builds before 10.0.14393.9688)
- Windows Server 2019 incl. Server Core (builds before 10.0.17763.9487)
- Windows Server 2022 (builds before 10.0.20348.5870)
- Windows Server 2025: not listed in the CNA record; third-party data only, unverified
Fixed in
- Fixed in the November 2026 security updates for the builds listed above. Verify the exact build numbers and the KB article for each product on the MSRC page.
Workaround
Unknown.
Exploitation
- No known exploitation in the wild.
- No CISA KEV entry and no public proof of concept known at the time of writing.
- CISA SSVC: exploitation none, automatable no, technical impact total.
Our recommendation
- Install the November 2026 security updates on all affected Windows systems, prioritising terminal servers, file servers and multi-user workstations.
- Verify the installed build numbers against the MSRC page, as the sources disagree on some entries.
- Limit local logon rights on servers and remove unneeded local accounts.
- Monitor for a public proof of concept or KEV listing and recheck the exploitation status in the coming weeks.
Information from Microsoft (Patch Tuesday November 2026)
- Severity (Microsoft)
- Important
- Impact
- Elevation of privilege – Windows Task Scheduler
- 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-2026-95894 msrc.microsoft.com
- CVE Record: CVE-2026-95894 www.cve.org
- Strix: CVE-2026-95894 (third-party, unverified) 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, 03:06.
Original description (NVD)
Heap-based buffer overflow in Windows Task Scheduler 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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