Windows AppX Package Manager: Heap overflow enables local privilege escalation
Summary
A heap-based buffer overflow (CWE-122) in the Windows AppX Package Manager allows an authorized local user to elevate privileges. An attacker needs code execution or an account with low privileges on the affected system. The impact is high on confidentiality, integrity and availability. The CNA rates the CVSS score at 7.8 (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).
Affected
- Windows 10 Version 1607 and Windows Server 2016 (incl. Server Core): before 10.0.14393.9688
- Windows 10 Version 1809 and Windows Server 2019 (incl. Server Core): before 10.0.17763.9487
- Windows 10 Version 21H2: before 10.0.19044.7846
- Windows 10 Version 22H2: before 10.0.19045.7846
- Windows 11 Version 23H2: before 10.0.22631.7711
- Windows 11 Version 24H2, 25H2 and 26H2: before 10.0.26100.9974, 10.0.26200.9974 and 10.0.26300.9974
- Windows 11 Version 26H1: before 10.0.28000.3501
- Windows Server 2022: before 10.0.20348.5870
Fixed in
Fixed in the November 2026 cumulative update. The build numbers are taken from the CVE record and must be verified against the MSRC advisory before rollout. The KB number KB5131096 comes from a third-party page and is unverified.
Workaround
- No vendor workaround known.
- Limit interactive local logons on shared, multi-user and terminal server systems.
- Prevent standard users from running untrusted software.
Exploitation
- CISA SSVC assessment: exploitation none, not automatable, total technical impact.
- No evidence of exploitation in the wild and no public proof of concept known at the time of research.
- EPSS: not available.
Our recommendation
- Deploy the November 2026 cumulative update, prioritising terminal servers and shared multi-user PCs.
- Check the client inventory for affected builds and for Windows 10 ESU coverage.
- Apply the workarounds until patching is complete and monitor for suspicious local privilege escalation.
- Priority: medium.
Information from Microsoft (Patch Tuesday November 2026)
- Severity (Microsoft)
- Important
- Impact
- Elevation of privilege – Windows AppX Package Manager
- Status on Patch Tuesday
- Neither exploited nor publicly disclosed
- Exploitability assessment
- Exploitation less likely
- Product family
- Windows, Windows ESU (Extended Security Updates)
- Updates (KB)
- KB5131085, KB5131090, KB5131096, KB5131080, KB5131077, KB5132061
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- CVE.org CNA record CVE-2026-96074 www.cve.org
- Microsoft Security Update Guide CVE-2026-96074 msrc.microsoft.com
- Strix CVE-2026-96074 (third-party, build list unverified) www.strix.ai
- Senserva KB5131096 (third-party) senserva.com
- Rapid7 Patch Tuesday November 2026 www.rapid7.com
- Tenable Patch Tuesday November 2026 www.tenable.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, 02:37.
Original description (NVD)
Heap-based buffer overflow in Windows AppX Package Manager 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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