VDB-340787 · CVE-2026-20857 · GCVE-0-2026-20857

Microsoft Windows up to Server 2025 Cloud Files Mini Filter Driver untrusted pointer dereference

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.
7.1	$5k-$25k	0.00

Summaryinfo

A vulnerability classified as critical has been found in Microsoft Windows. The impacted element is an unknown function of the component Cloud Files Mini Filter Driver. The manipulation leads to untrusted pointer dereference. This vulnerability is uniquely identified as CVE-2026-20857. Local access is required to approach this attack. No exploit exists. To fix this issue, it is recommended to deploy a patch.

Detailsinfo

A vulnerability, which was classified as critical, has been found in Microsoft Windows. This issue affects some unknown processing of the component Cloud Files Mini Filter Driver. The manipulation with an unknown input leads to a untrusted pointer dereference vulnerability. Using CWE to declare the problem leads to CWE-822. The product obtains a value from an untrusted source, converts this value to a pointer, and dereferences the resulting pointer. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

Untrusted pointer dereference in Windows Cloud Files Mini Filter Driver allows an authorized attacker to elevate privileges locally.

The weakness was disclosed 01/13/2026 as confirmed security update guide (Website). It is possible to read the advisory at msrc.microsoft.com. The identification of this vulnerability is CVE-2026-20857. The exploitation is known to be easy. Attacking locally is a requirement. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 01/16/2026).

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

Statistical analysis made it clear that VulDB provides the best quality for 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: 7.8
VulDB Meta Temp Score: 7.1

VulDB Base Score: 7.8
VulDB Temp Score: 6.8
VulDB Vector: 🔒
VulDB Reliability: 🔍

Vendor Base Score (Microsoft): 7.8
Vendor Vector (Microsoft): 🔒

CNA Base Score: 7.8
CNA Vector (Microsoft): 🔒

CVSSv2info

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

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

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

Exploitinginfo

Class: Untrusted pointer dereference
CWE: CWE-822
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 +3 days VulDB entry last update

Sourcesinfo

Vendor: microsoft.com
Product: microsoft.com

Advisory: msrc.microsoft.com
Status: Confirmed

CVE: CVE-2026-20857 (🔒)
GCVE (CVE): GCVE-0-2026-20857
GCVE (VulDB): GCVE-100-340787
scip Labs: https://www.scip.ch/en/?labs.20161215

Entryinfo

Created: 01/13/2026 19:32
Updated: 01/16/2026 12:57
Changes: 01/13/2026 19:32 (36), 01/13/2026 19:35 (33), 01/16/2026 12:57 (11)
Complete: 🔍
Cache ID: 216::103