Local RCE in Windows NTFS Heap-Based Buffer Overflow
CVE-2026-20840 is a heap-based buffer overflow vulnerability in Windows NTFS. Microsoft and multiple contemporaneous Patch Tuesday summaries describe it as an Important-severity Windows NTFS remote code execution issue with CVSS 7.8, although exploitation is characterized as local: an authorized attacker can trigger the heap overflow on a vulnerable system and achieve arbitrary code execution. Microsoft assessed the flaw as 'Exploitation More Likely.' Public reporting attributes discovery to Sergey Tarasov of Positive Technologies, but the provided content does not identify the specific NTFS function or code path involved.
Are you exposed to this one?
Mallory correlates every CVE against your assets, your vendors, and active adversary campaigns. Know which vulnerabilities matter for you, not just which ones are loud.
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.
Mitigation
If you can’t patch tonight, do this now.
Remediation
Patch, then assume compromise.
Exploits
No public exploits tracked yet. Mallory keeps watching.
No public exploit code observed for this vulnerability.
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.
Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
Recent activity
11 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
Windows NTFS remote code execution vulnerability assessed as 'Exploitation More Likely' by Microsoft; no exploitation reported in the content.
A Windows NTFS heap-based buffer overflow that can lead to arbitrary code execution; assessed by Microsoft as 'Exploitation More Likely'.
A remote code execution vulnerability in Windows NTFS that Microsoft assessed as more likely to be exploited.
A heap-based buffer overflow in Windows NTFS that can lead to code execution (described as RCE, with local execution context in the content).
The version that knows your environment.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.