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Known Exploited Vulnerability
5.5
MEDIUM CVSS 3.1
CVE-2021-31955
Microsoft Windows Kernel Information Disclosure Vulnerability - [Actively Exploited]
Description

Windows Kernel Information Disclosure Vulnerability

INFO

Published Date :

June 8, 2021, 11:15 p.m.

Last Modified :

Oct. 30, 2025, 7:40 p.m.

Remotely Exploit :

No

Source :

[email protected]
CISA Notification
CISA KEV (Known Exploited Vulnerabilities)

For the benefit of the cybersecurity community and network defenders—and to help every organization better manage vulnerabilities and keep pace with threat activity—CISA maintains the authoritative source of vulnerabilities that have been exploited in the wild.

Description :

Microsoft Windows Kernel contains an unspecified vulnerability that allows for information disclosure. Successful exploitation allows attackers to read the contents of kernel memory from a user-mode process.

Required Action :

Apply updates per vendor instructions.

Notes :

https://nvd.nist.gov/vuln/detail/CVE-2021-31955

Affected Products

The following products are affected by CVE-2021-31955 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Microsoft windows_10
2 Microsoft windows_server_2016
3 Microsoft windows_server_2019
4 Microsoft windows_10_1809
5 Microsoft windows_10_20h2
6 Microsoft windows_10_21h1
7 Microsoft windows_10_1909
8 Microsoft windows_server_20h2
9 Microsoft windows_10_2004
10 Microsoft windows_server_2004
: Total Affected Vendor : 1 | Products : 10
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 2.0 LOW [email protected]
CVSS 3.1 MEDIUM [email protected]
CVSS 3.1 MEDIUM [email protected]
Solution
A vulnerability in Microsoft Windows could allow for information disclosure.
  • Apply the latest cumulative update for your version of Windows.
  • Reboot the system.
Public PoC/Exploit Available at Github

CVE-2021-31955 has a 8 public PoC/Exploit available at Github. Go to the Public Exploits tab to see the list.

References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2021-31955.

URL Resource
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31955 Patch Vendor Advisory
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31955 Patch Vendor Advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-31955 US Government Resource
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2021-31955 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2021-31955 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Profile Photo
ApexPredator-InfoSec/forti_shield

A combined POC for CVE-2021-31955, CVE-2015-4077, and CVE-2015-5736

C++ C Assembly

Updated: 1 day, 16 hours ago
0 stars 0 fork 0 watcher
Born at : Oct. 29, 2025, 6:16 p.m. This repo has been linked 3 different CVEs too.
Profile Photo
NaInSec/CVE-PoC-in-GitHub

All CVE - PoC in GitHub

poc proofofconcept tester allcve cvegithub cvenew cvepoc cveupdate

Updated: 4 months, 4 weeks ago
12 stars 3 fork 3 watcher
Born at : March 22, 2024, 3:58 p.m. This repo has been linked 931 different CVEs too.
Profile Photo
zecool/cve

None

Updated: 4 months, 1 week ago
2 stars 0 fork 0 watcher
Born at : March 11, 2024, 1:21 p.m. This repo has been linked 935 different CVEs too.
Profile Photo
hoangprod/CVE-2021-31956-POC

None

C C++

Updated: 3 months, 3 weeks ago
3 stars 1 fork 1 watcher
Born at : June 5, 2023, 12:03 a.m. This repo has been linked 2 different CVEs too.
Profile Photo
WhooAmii/POC_to_review

None

Updated: 5 months, 1 week ago
2 stars 2 fork 2 watcher
Born at : Nov. 25, 2022, 5:43 p.m. This repo has been linked 935 different CVEs too.
Profile Photo
soosmile/POC

None

Updated: 6 months, 4 weeks ago
9 stars 1 fork 1 watcher
Born at : June 21, 2022, 7:45 a.m. This repo has been linked 944 different CVEs too.
Profile Photo
Ostorlab/KEV

Ostorlab KEV: One-command to detect most remotely known exploitable vulnerabilities. Sourced from CISA KEV, Google's Tsunami, Ostorlab's Asteroid and Bug Bounty programs.

cisa-kev vulnerability 0day cisa exploits

Updated: 2 weeks, 6 days ago
588 stars 42 fork 42 watcher
Born at : April 19, 2022, 8:58 a.m. This repo has been linked 1290 different CVEs too.
Profile Photo
freeide/CVE-2021-31955-POC

None

C++ C

Updated: 3 months, 3 weeks ago
12 stars 21 fork 21 watcher
Born at : June 26, 2021, 3:59 a.m. This repo has been linked 1 different CVEs too.

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2021-31955 vulnerability anywhere in the article.

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2021-31955 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • Modified Analysis by [email protected]

    Oct. 30, 2025

    Action Type Old Value New Value
    Added Reference Type CISA-ADP: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-31955 Types: US Government Resource
  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Oct. 22, 2025

    Action Type Old Value New Value
    Added Reference https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-31955
  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Oct. 21, 2025

    Action Type Old Value New Value
    Removed Reference https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-31955
  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Oct. 21, 2025

    Action Type Old Value New Value
    Added Reference https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-31955
  • Modified Analysis by [email protected]

    Mar. 07, 2025

    Action Type Old Value New Value
  • CVE Modified by af854a3a-2127-422b-91ae-364da2661108

    Nov. 21, 2024

    Action Type Old Value New Value
    Added Reference https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31955
  • Modified Analysis by [email protected]

    Jul. 29, 2024

    Action Type Old Value New Value
    Removed CWE NIST CWE-200
    Added CWE NIST NVD-CWE-noinfo
    Changed CPE Configuration OR *cpe:2.3:o:microsoft:windows_10:20h2:*:*:*:*:*:*:* *cpe:2.3:o:microsoft:windows_10:21h1:*:*:*:*:*:*:* *cpe:2.3:o:microsoft:windows_10:1809:*:*:*:*:*:*:* *cpe:2.3:o:microsoft:windows_10:1909:*:*:*:*:*:*:* *cpe:2.3:o:microsoft:windows_10:2004:*:*:*:*:*:*:* *cpe:2.3:o:microsoft:windows_server_2016:20h2:*:*:*:*:*:*:* *cpe:2.3:o:microsoft:windows_server_2016:2004:*:*:*:*:*:*:* *cpe:2.3:o:microsoft:windows_server_2019:-:*:*:*:*:*:*:* OR *cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:*:* versions up to (excluding) 10.0.17763.1999 *cpe:2.3:o:microsoft:windows_10_1909:*:*:*:*:*:*:*:* versions up to (excluding) 10.0.18363.1621 *cpe:2.3:o:microsoft:windows_10_2004:*:*:*:*:*:*:*:* versions up to (excluding) 10.0.19041.1052 *cpe:2.3:o:microsoft:windows_10_20h2:*:*:*:*:*:*:*:* versions up to (excluding) 10.0.19042.1052 *cpe:2.3:o:microsoft:windows_10_21h1:*:*:*:*:*:*:*:* versions up to (excluding) 10.0.19043.1052 *cpe:2.3:o:microsoft:windows_server_2004:*:*:*:*:*:*:*:* versions up to (excluding) 10.0.19041.1052 *cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:*:* versions up to (excluding) 10.0.17763.1999 *cpe:2.3:o:microsoft:windows_server_20h2:*:*:*:*:*:*:*:* versions up to (excluding) 10.0.19042.1052
  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Jul. 03, 2024

    Action Type Old Value New Value
    Added CWE CISA-ADP CWE-497
  • CVE Modified by [email protected]

    May. 14, 2024

    Action Type Old Value New Value
  • CVE Modified by [email protected]

    Aug. 01, 2023

    Action Type Old Value New Value
    Added CVSS V3.1 Microsoft Corporation AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
  • Initial Analysis by [email protected]

    Jun. 10, 2021

    Action Type Old Value New Value
    Added CVSS V2 NIST (AV:L/AC:L/Au:N/C:P/I:N/A:N)
    Added CVSS V3.1 NIST AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
    Changed Reference Type https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31955 No Types Assigned https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31955 Patch, Vendor Advisory
    Added CWE NIST CWE-200
    Added CPE Configuration OR *cpe:2.3:o:microsoft:windows_10:20h2:*:*:*:*:*:*:* *cpe:2.3:o:microsoft:windows_10:21h1:*:*:*:*:*:*:* *cpe:2.3:o:microsoft:windows_10:1809:*:*:*:*:*:*:* *cpe:2.3:o:microsoft:windows_10:1909:*:*:*:*:*:*:* *cpe:2.3:o:microsoft:windows_10:2004:*:*:*:*:*:*:* *cpe:2.3:o:microsoft:windows_server_2016:20h2:*:*:*:*:*:*:* *cpe:2.3:o:microsoft:windows_server_2016:2004:*:*:*:*:*:*:* *cpe:2.3:o:microsoft:windows_server_2019:-:*:*:*:*:*:*:*
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
Vulnerability Scoring Details
Base CVSS Score: 5.5
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality Impact
Integrity Impact
Availability Impact
Base CVSS Score: 2.1
Access Vector
Access Complexity
Authentication
Confidentiality Impact
Integrity Impact
Availability Impact
Exploit Prediction

EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days.

15.54 }} 3.27%

score

0.94375

percentile