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Mallory
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Local RCE in Windows NTFS Heap-Based Buffer Overflow

IdentifiersCVE-2026-20922CWE-122· Heap-based Buffer Overflow

CVE-2026-20922 is a Windows NTFS remote code execution vulnerability caused by a heap-based buffer overflow in the NTFS component. Microsoft and secondary reporting describe it as an Important-severity issue with CVSS 7.8 and classify it as 'Exploitation More Likely.' The flaw allows an authorized attacker to execute code locally. Public reporting does not provide the specific vulnerable NTFS function or code path, so the exact trigger condition beyond local interaction with the vulnerable NTFS component is currently not available.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation allows local arbitrary code execution in the context achieved through the vulnerable NTFS path. Depending on the attacker’s starting privileges and the targeted workflow, this can enable execution of attacker-controlled code on the host and may serve as a stepping stone to broader system compromise as part of a post-compromise or multi-stage attack chain.

Mitigation

If you can’t patch tonight, do this now.

If immediate patching is not possible, reduce opportunities for local exploitation by limiting untrusted local access, restricting execution of untrusted code, and minimizing attacker ability to interact with vulnerable NTFS-backed workflows. Apply least-privilege controls, harden endpoints against post-compromise activity, and increase monitoring for suspicious local execution and abnormal filesystem activity. These measures are only compensating controls; vendor patching is the primary mitigation.

Remediation

Patch, then assume compromise.

Apply the January 2026 Microsoft security updates that address CVE-2026-20922 on all affected Windows systems. Because Microsoft assessed the issue as 'Exploitation More Likely' and external reporting noted the possibility that technical details could become public quickly, patching should be prioritized. Validate that affected Windows builds have been updated through normal patch-management and compliance processes.
PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType
Microsoft CorporationWindows 10 1607operating_system
Microsoft CorporationWindows 10 1809operating_system
Microsoft CorporationWindows 10 21h2operating_system
Microsoft CorporationWindows 10 22h2operating_system
Microsoft CorporationWindows 11 23h2operating_system
Microsoft CorporationWindows 11 24h2operating_system
Microsoft CorporationWindows 11 25h2operating_system
Microsoft CorporationWindows Server 2008operating_system
Microsoft CorporationWindows Server 2008 R2operating_system
Microsoft CorporationWindows Server 2008 Sp2operating_system
Microsoft CorporationWindows Server 2012operating_system
Microsoft CorporationWindows Server 2012 R2operating_system
Microsoft CorporationWindows Server 2016operating_system
Microsoft CorporationWindows Server 2019operating_system
Microsoft CorporationWindows Server 2022operating_system
Microsoft CorporationWindows Server 2022 23h2operating_system
Microsoft CorporationWindows Server 2025operating_system
Microsoft CorporationWindows Server 23h2operating_system

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

What this page doesn’t show

The version that knows your environment.

This page is what’s public. Mallory adds the parts that aren’t: which of your assets are affected, which adversaries are exploiting it right now, which detections to deploy, and what to do tonight.
Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures1

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity4

Community discussion across Reddit, Mastodon, and other social sources.