VDB-340753 · CVE-2026-20818 · GCVE-0-2026-20818

Microsoft Windows up to Server 2025 Kernel log file

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
4.8	$0-$5k	0.00

Summaryinfo

A vulnerability was found in Microsoft Windows Server 2016/Server 2019/Server 2022/Server 2022 23H2/Server 2025. It has been rated as problematic. The affected element is an unknown function of the component Kernel. This manipulation causes log file. This vulnerability appears as CVE-2026-20818. The attack requires local access. There is no available exploit. It is suggested to install a patch to address this issue.

Detailsinfo

A vulnerability has been found in Microsoft Windows Server 2016/Server 2019/Server 2022/Server 2022 23H2/Server 2025 and classified as problematic. Affected by this vulnerability is an unknown function of the component Kernel. The manipulation with an unknown input leads to a log file vulnerability. The CWE definition for the vulnerability is CWE-532. Information written to log files can be of a sensitive nature and give valuable guidance to an attacker or expose sensitive user information. As an impact it is known to affect confidentiality. The summary by CVE is:

Insertion of sensitive information into log file in Windows Kernel allows an unauthorized attacker to disclose information locally.

The weakness was presented 01/13/2026 as confirmed security update guide (Website). The advisory is shared at msrc.microsoft.com. This vulnerability is known as CVE-2026-20818. The exploitation appears to be easy. An attack has to be approached locally. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 01/16/2026). MITRE ATT&CK project uses the attack technique T1592 for this issue.

Applying a patch is able to eliminate this problem. A possible mitigation has been published immediately after the disclosure of the vulnerability.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

Operating System

Vendor

Microsoft

Name

Windows

Version

License

commercial

Website

Vendor: https://www.microsoft.com/
Product: https://www.microsoft.com/en-us/windows

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.2
VulDB Meta Temp Score: 4.8

VulDB Base Score: 3.3
VulDB Temp Score: 2.9
VulDB Vector: 🔒
VulDB Reliability: 🔍

Vendor Base Score (Microsoft): 6.2
Vendor Vector (Microsoft): 🔒

CNA Base Score: 6.2
CNA Vector (Microsoft): 🔒

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Log file
CWE: CWE-532 / CWE-200 / CWE-284
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: No

Availability: 🔒
Status: Unproven

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Patch
Status: 🔍

Reaction Time: 🔒
0-Day Time: 🔒
Exposure Time: 🔒

Timelineinfo

01/13/2026 VulDB entry created
01/13/2026 +0 days Advisory disclosed
01/13/2026 +0 days Countermeasure disclosed
01/16/2026 +2 days VulDB entry last update

Sourcesinfo

Vendor: microsoft.com
Product: microsoft.com

Advisory: msrc.microsoft.com
Status: Confirmed

CVE: CVE-2026-20818 (🔒)
GCVE (CVE): GCVE-0-2026-20818
GCVE (VulDB): GCVE-100-340753

Entryinfo

Created: 01/13/2026 19:17
Updated: 01/16/2026 07:21
Changes: 01/13/2026 19:17 (34), 01/13/2026 19:20 (35), 01/16/2026 07:21 (12)
Complete: 🔍
Cache ID: 216::103