CVE-2026-20840
published 2026-01-13CVE-2026-20840: Heap-based buffer overflow in Windows NTFS allows an authorized attacker to execute code locally.
PriorityP355high7.8CVSS 3.1
AVLACLPRLUINSUCHIHAH
EPSS
2.42%
82.3th percentile
Heap-based buffer overflow in Windows NTFS allows an authorized attacker to execute code locally.
Affected
45 ranges· showing 25
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| microsoft | windows_10_1607 | < 10.0.14393.8783 | 10.0.14393.8783 |
| microsoft | windows_10_1809 | < 10.0.17763.8276 | 10.0.17763.8276 |
| microsoft | windows_10_21h2 | < 10.0.19044.6809 | 10.0.19044.6809 |
| microsoft | windows_10_22h2 | < 10.0.19045.6809 | 10.0.19045.6809 |
| microsoft | windows_10_version_1607 | >= 10.0.14393.0 < 10.0.14393.8783 | 10.0.14393.8783 |
| microsoft | windows_10_version_1809 | >= 10.0.17763.0 < 10.0.17763.8276 | 10.0.17763.8276 |
| microsoft | windows_10_version_21h2 | >= 10.0.19044.0 < 10.0.19044.6809 | 10.0.19044.6809 |
| microsoft | windows_10_version_22h2 | >= 10.0.19045.0 < 10.0.19045.6809 | 10.0.19045.6809 |
| microsoft | windows_11_23h2 | < 10.0.22631.6491 | 10.0.22631.6491 |
| microsoft | windows_11_24h2 | < 10.0.26100.7623 | 10.0.26100.7623 |
| microsoft | windows_11_25h2 | < 10.0.26200.7623 | 10.0.26200.7623 |
| microsoft | windows_11_version_22h3 | >= 10.0.22631.0 < 10.0.22631.6491 | 10.0.22631.6491 |
| microsoft | windows_11_version_23h2 | >= 10.0.22631.0 < 10.0.22631.6491 | 10.0.22631.6491 |
| microsoft | windows_11_version_24h2 | >= 10.0.26100.0 < 10.0.26100.7623 | 10.0.26100.7623 |
| microsoft | windows_11_version_25h2 | >= 10.0.26200.0 < 10.0.26200.7623 | 10.0.26200.7623 |
| microsoft | windows_server_2008 | — | — |
| microsoft | windows_server_2008_r2_service_pack_1 | >= 6.1.7601.0 < 6.1.7601.28117 | 6.1.7601.28117 |
| microsoft | windows_server_2008_service_pack_2 | >= 6.0.6003.0 < 6.0.6003.23717 | 6.0.6003.23717 |
| microsoft | windows_server_2012 | — | — |
| microsoft | windows_server_2012 | >= 6.2.9200.0 < 6.2.9200.25868 | 6.2.9200.25868 |
| microsoft | windows_server_2012_r2 | >= 6.3.9600.0 < 6.3.9600.22968 | 6.3.9600.22968 |
| microsoft | windows_server_2016 | < 10.0.14393.8783 | 10.0.14393.8783 |
| microsoft | windows_server_2016 | >= 10.0.14393.0 < 10.0.14393.8783 | 10.0.14393.8783 |
| microsoft | windows_server_2019 | < 10.0.17763.8276 | 10.0.17763.8276 |
| microsoft | windows_server_2019 | >= 10.0.17763.0 < 10.0.17763.8276 | 10.0.17763.8276 |
CVSS provenance
nvdv3.17.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
vendor_msrc7.8HIGH
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Microsoft
Windows NTFS Remote Code Execution Vulnerability
vendor_msrc·2026-01-13·CVSS 7.8
CVE-2026-20840 [HIGH] CWE-122 Windows NTFS Remote Code Execution Vulnerability
Windows NTFS Remote Code Execution Vulnerability
Description: Heap-based buffer overflow in Windows NTFS allows an authorized attacker to execute code locally.
FAQ: According to the CVSS metric, the attack vector is local (AV:L). Why does the CVE title indicate that this is a remote code execution?
The word Remote in the title refers to the location of the attacker. This type of exploit is sometimes referred to as Arbitrary Code Execution (ACE). The attack itself is carried out locally. This means an attacker or victim needs to execute code from the local machine to exploit the vulnerability.
FAQ: According to the CVSS metric, privileges required is low (PR:L). What does that mean for this vulnerability?
Any authenticated attacker could trigger this vulnerability. It does not require ad
GHSA
GHSA-5vxv-h86v-8rwc: Heap-based buffer overflow in Windows NTFS allows an authorized attacker to execute code locally
ghsa_unreviewed·2026-01-13
CVE-2026-20840 [HIGH] CWE-122 GHSA-5vxv-h86v-8rwc: Heap-based buffer overflow in Windows NTFS allows an authorized attacker to execute code locally
Heap-based buffer overflow in Windows NTFS allows an authorized attacker to execute code locally.
No detection rules found.
No public exploits indexed.
Tenable
Microsoft’s January 2026 Patch Tuesday Addresses 113 CVEs (CVE-2026-20805)
blogs_tenable·2026-01-13·CVSS 5.5
[MEDIUM] Microsoft’s January 2026 Patch Tuesday Addresses 113 CVEs (CVE-2026-20805)
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Qualys
Microsoft and Adobe Patch Tuesday, January 2026 Security Update Review
blogs_qualys·2026-01-13
Microsoft and Adobe Patch Tuesday, January 2026 Security Update Review
## Table of Contents
Microsoft Patch Tuesday forJanuary2026
Adobe Patches for January 2026
Zero-day Vulnerabilities Patched inJanuaryPatch Tuesday Edition
Critical Severity Vulnerabilities Patched inJanuaryPatch Tuesday Edition
Other Microsoft Vulnerability Highlights
Microsoft Release Summary
Discover and Prioritize Vulnerabilities inVulnerability Management, Detection & Response (VMDR)
Rapid Response with TruRisk Eliminate
EVALUATE Vendor-Suggested Mitigation withPolicy Audit(PA)
Qualys Monthly Webinar Series
Starting the year on a security-first note, Microsoft’s January 2026 Patch Tuesday resolves several vulnerabilities that could impact enterprise environments. Here’s a quick breakdown of what you need to know.
## Microsoft Patch Tuesday for January 2026
This month’s rel
Bleepingcomputer
Microsoft January 2026 Patch Tuesday fixes 3 zero-days, 114 flaws
blogs_bleepingcomputer·2026-01-13·CVSS 5.5
[MEDIUM] Microsoft January 2026 Patch Tuesday fixes 3 zero-days, 114 flaws
## Microsoft January 2026 Patch Tuesday fixes 3 zero-days, 114 flaws
## Lawrence Abrams
57 Elevation of Privilege vulnerabilities
3 Security Feature Bypass vulnerabilities
22 Remote Code Execution vulnerabilities
22 Information Disclosure vulnerabilities
2 Denial of Service vulnerabilities
5 Spoofing vulnerabilities
When BleepingComputer reports on Patch Tuesday security updates, we only count those released by Microsoft today. Therefore, the number of flaws does not include Microsoft Edge (1 flaw) and Mariner vulnerabilities fixed earlier this month.
To learn more about the non-security updates released today, you can review our dedicated articles on the Windows 11 KB5074109 & KB5073455 cumulative updates and Windows 10 KB5073724 extended security update .
## 3 zero-days, one ex
Talos
Microsoft Patch Tuesday for January 2026 — Snort rules and prominent vulnerabilities
blogs_talos·2026-01-13·CVSS 5.5
CVE-2026-20805 [MEDIUM] Microsoft Patch Tuesday for January 2026 — Snort rules and prominent vulnerabilities
## Microsoft Patch Tuesday for January 2026 — Snort rules and prominent vulnerabilities
Microsoft has released its monthly security update for January 2026, which includes 112 vulnerabilities affecting a range of products, including 8 that Microsoft marked as “critical”.
In this month's release, Microsoft observed one of the included “important” vulnerabilities, CVE-2026-20805 , as being exploited in the wild. Out of 8 "critical" entries, 6 are remote code execution (RCE) vulnerabilities in Microsoft Windows services and applications including Windows Local Security Authority Subsystem Service (LSASS), Microsoft Word, Microsoft Excel, and Microsoft Office. The two remaining “critical” entries are elevation of privilege (EoP) vulnerabilities affecting Windows Graphic Component and Windows
Talos
Microsoft Patch Tuesday for January 2026 — Snort rules and prominent vulnerabilities
blogs_talos·2026-01-13·CVSS 5.5
CVE-2026-20805 [MEDIUM] Microsoft Patch Tuesday for January 2026 — Snort rules and prominent vulnerabilities
Microsoft has released its monthly security update for January 2026, which includes 112 vulnerabilities affecting a range of products, including 8 that Microsoft marked as “critical”.
In this month's release, Microsoft observed one of the included “important” vulnerabilities, CVE-2026-20805, as being exploited in the wild. Out of 8 "critical" entries, 6 are remote code execution (RCE) vulnerabilities in Microsoft Windows services and applications including Windows Local Security Authority Subsystem Service (LSASS), Microsoft Word, Microsoft Excel, and Microsoft Office. The two remaining “critical” entries are elevation of privilege (EoP) vulnerabilities affecting Windows Graphic Component and Windows Virtualization-Based Security (VBS) Enclave.
CVE-2026-20822 is a critical elevation of p
Qualys
Microsoft and Adobe Patch Tuesday, January 2026 Security Update Review | Qualys
blogs_qualys·2026-01-13
Microsoft and Adobe Patch Tuesday, January 2026 Security Update Review | Qualys
#### Table of Contents
- Microsoft Patch Tuesday forJanuary2026
- Adobe Patches for January 2026
- Zero-day Vulnerabilities Patched inJanuaryPatch Tuesday Edition
- Critical Severity Vulnerabilities Patched inJanuaryPatch Tuesday Edition
- Other Microsoft Vulnerability Highlights
- Microsoft Release Summary
- Discover and Prioritize Vulnerabilities inVulnerability Management, Detection & Response (VMDR)
- Rapid Response with TruRisk Eliminate
- EVALUATE Vendor-Suggested Mitigation withPolicy Audit(PA)
- Qualys Monthly Webinar Series
Starting the year on a security-first note, Microsoft’s January 2026 Patch Tuesday resolves several vulnerabilities that could impact enterprise environments. Here’s a quick breakdown of what you need to know.
## Microsoft Patch Tuesday for January 2026
Thi
Wiz
CVE-2026-20840 Impact, Exploitability, and Mitigation Steps | Wiz
blogs_wiz·CVSS 7.8
CVE-2026-20840 [HIGH] CVE-2026-20840 Impact, Exploitability, and Mitigation Steps | Wiz
## CVE-2026-20840 :
vulnerability analysis and mitigation
Heap-based buffer overflow in Windows NTFS allows an authorized attacker to execute code locally.
Source : NVD
## 7.8
Score
Published January 13, 2026
Severity HIGH
CNA Score 7.8
Has Public Exploit No
Has CISA KEV Exploit No
CISA KEV Release Date N/A
CISA KEV Due Date N/A
Exploitation Probability Percentile (EPSS) 7.4
Exploitation Probability (EPSS) N/A
Sources
NVD
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Zscaler protects against 9 new vulnerabilities | 01-13-2026
blogs_zscaler·CVSS 5.5
[MEDIUM] Zscaler protects against 9 new vulnerabilities | 01-13-2026
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2026-01-13
Published