VDB-188227 · CVE-2021-43217 · WID-SEC-2025-2220

Microsoft Windows up to Server 2022 Encrypting File System Remote Code Execution

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 marked as very critical has been reported in Microsoft Windows. The affected element is an unknown function of the component Encrypting File System. This manipulation causes an unknown weakness. This vulnerability is tracked as CVE-2021-43217. The attack is possible to be carried out remotely. No exploit exists. To fix this issue, it is recommended to deploy a patch.

Detailsinfo

A vulnerability classified as very critical was found in Microsoft Windows (Operating System). Affected by this vulnerability is an unknown code of the component Encrypting File System. As an impact it is known to affect confidentiality, integrity, and availability.

The weakness was disclosed 12/14/2021 as confirmed security guidance (Website). It is possible to read the advisory at portal.msrc.microsoft.com. This vulnerability is known as CVE-2021-43217. 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 10/07/2025).

We expect the 0-day to have been worth approximately $100k and more.

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

The vulnerability is also documented in the vulnerability database at CERT Bund (WID-SEC-2025-2220). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Affected

Microsoft Windows 7 x64 Edition Service Pack 1
Microsoft Windows RT 8.1
Microsoft Windows 8.1 for x64-based Systems
Microsoft Windows 10
Microsoft Windows Server 2012
Microsoft Windows Server 2016
Hitachi Storage
Microsoft Windows Server 2008 Service Pack 2
Microsoft Windows Server 2008 R2
Microsoft Windows Server 2019
Microsoft Windows Server 2012 R2
Microsoft Windows Server
Microsoft Windows Server 2022
Microsoft Windows 11

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: 8.1
VulDB Meta Temp Score: 7.1

VulDB Base Score: 8.1
VulDB Temp Score: 7.1
VulDB Vector: 🔍
VulDB Reliability: 🔍

Vendor Base Score (Microsoft): 8.1
Vendor 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: Remote Code Execution
CWE: Unknown
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

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

11/02/2021 🔍
12/14/2021 +42 days 🔍
12/14/2021 +0 days 🔍
12/15/2021 +0 days 🔍
10/07/2025 +1392 days 🔍

Sourcesinfo

Vendor: microsoft.com
Product: microsoft.com

Advisory: portal.msrc.microsoft.com
Status: Confirmed

CVE: CVE-2021-43217 (🔍)
GCVE (CVE): GCVE-0-2021-43217
GCVE (VulDB): GCVE-100-188227
CERT Bund: WID-SEC-2025-2220 - Microsoft Windows und Microsoft Windows Server: Mehrere Schwachstellen

scip Labs: https://www.scip.ch/en/?labs.20161215

Entryinfo

Created: 12/15/2021 05:40
Updated: 10/07/2025 19:09
Changes: 12/15/2021 05:40 (14), 12/15/2021 05:41 (20), 12/15/2021 05:44 (21), 12/17/2021 13:27 (2), 10/07/2025 19:09 (22)
Complete: 🔍
Cache ID: 216::103

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.