vciy

CVE-2021-33739

INDEX BUILT · 2026-09-20

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Microsoft DWM Core Library Elevation of Privilege Vulnerability

CVE-2021-337394 of 4 sources documented this
65

rank 65 = 40 + 12 + 1 + 6 + 6

rank@v1 · this cycle

Someone is already using it

CISA KEV catalog · public proof-of-concept · FIRST EPSS

EPSS 0.06555 · CISA KEV listed  ·  without this subject the record ranks 25

What it costs you if it fires

NVD CVSS base score, then the CNA's own

CVSS 4.6, from NVD  ·  without this subject the record ranks 53

It is getting worse, not staying still

FIRST EPSS series, rescorings and bad loads removed

rose on 2025-12-07  ·  without this subject the record ranks 64

How much of the world it touches

NVD CPE configurations

6 products in the CPE ranges  ·  without this subject the record ranks 59

Someone else already set the date

CISA KEV remediation due date

CISA remediation date held  ·  without this subject the record ranks 59

Unaudited dollar value2 of 3 inputs carry a receipt
Exposure$327,000over the next 30 days, if this record is yours
Movement-$812,000on 2022-02-04, the last material move, 4 years, 7 months before this reading
Basisassumeda published average, not your estate

$327,000 = $4.99M incident cost x 1 exposure x 0.06555 likelihood

udv@v1 · unaudited · wrong for you until you say what you run

$4.99M is the cost of a breach that happened, from IBM Cost of a Data Breach Report 2026, global average. It is not the value of any asset of yours. That average already covers breaches of every severity, so scaling it by exposure understates a partial-impact record. That is an assumption, not a measurement. Your own asset value goes in the decision record.

Hindsight · the state

0.06555EPSSKEV · LISTED
Severity8.4 HIGHreceipt
Harmtotal lossreceipt
Exploitationin the wild · KEVreceipt
Defensefix version namedreceipt
Movementthreshold crossedreceipt
RISING10Risen from 0.0184 to 0.06555 across 46 observations. arc-rules@v1

Foresight · where to check next

No weakness class or product neighbourhood is held for this record, so this index cannot name anywhere to check next. That is an absence in the record, not a finding about the software.

Color is a claim, not decoration:the hostile worldthe defenseno signal

Sources disagree here.

Severity score
Microsoft8.4 HIGHreceipt
NVD4.6 MEDIUMreceipt
Scoring standard
MicrosoftCVSS v3.1receipt
NVDCVSS v2.0receipt

Both shown, dated. We don't pick winners. disagreement-rules@v1

Running Microsoft Windows 10 Version 1909? Check your version

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Harm, if it fires from the vector and the weakness

Written for the ticket you're about to file.

Reachneeds local access · no privileges required · no user interaction · low attack complexityreceipt
ImpactComplete confidentiality, integrity and availability lossreceipt
Scored fromCVSS v3.1 · the CNA's vectorreceipt
Weakness classNo CWE mapping in held sources.
Ransomware campaign useUnknown to CISAreceipt

CISA KEV & Federal Remediation Deadline from the record and CISA

The fix, and how long it's been waiting.

Fixed in10.0.18363.1621; 10.0.19043.1052; 10.0.19041.1052; 10.0.19042.1052receipt
Patch available sinceNo dated patch-availability record in held sources. The index holds reference URLs without dates and only the current revision of the CVE record, so the day a fix first existed cannot be derived. Only the versions it landed in.
CISA remediation statusoverdue since 2021-11-17receipt
CISA required actionApply updates per vendor instructions.receipt
Published to CISA KEV148 daysderived

Exploit Status & Known PoCs a ladder, not a score

Current rung: Exploited in the wild · CISA KEV listed, 2021-11-03.

  • RUNG 1Nothing observed in held sources
  • RUNG 2Proof-of-concept published · 2 public repositories2021-06-09receipt
  • RUNG 3Exploited in the wild · CISA KEV listed2021-11-03receipt
  • RUNG 4Ransomware campaign use known

Authority who says so

CVSS, the CNA8.4 HIGHreceipt
CVSS, NVD4.6 MEDIUMreceipt
Exploit probability0.06555 · top 7% of all CVEsreceipt
Blast breadth3 products across 1 vendorderived
Assigned bymicrosoftreceipt
Recorded changes60 · last 19 Sep 2026derived

Affected & Fixed Versions as published

Affected productMicrosoft Windows 10 Version 1909; Microsoft Windows 10 Version 21H1; Microsoft Windows 10 Version 2004; Microsoft Windows Server version 2004; Microsoft Windows 10 Version 20H2…receipt
Published rangesmicrosoft windows 10 1909 < 10.0.18363.1621; microsoft windows 10 2004 < 10.0.19041.1052; microsoft windows 10 20h2 < 10.0.19042.1052; microsoft windows 10 21h1 < 10.0.19043.1052receipt
Show all 6 published ranges
microsoft windows 10 1909 < 10.0.18363.1621
microsoft windows 10 2004 < 10.0.19041.1052
microsoft windows 10 20h2 < 10.0.19042.1052
microsoft windows 10 21h1 < 10.0.19043.1052
microsoft windows server 2004 < 10.0.19041.1052
microsoft windows server 20h2 < 10.0.19042.1052
Fixed in10.0.18363.1621; 10.0.19043.1052; 10.0.19041.1052; 10.0.19042.1052receipt

A rung lights from a row in the index, never from an assessment. "Held sources" is the true scope of the claim: this index reads the CVE record, NVD, CISA KEV, FIRST's EPSS and public proof-of-concept repositories, and it does not observe attacks.

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What it is stated by the CNA

Microsoft DWM Core Library Elevation of Privilege Vulnerability receipt

NVD's analysis a second authority

severity
4.6 AV:L/AC:L/Au:N/C:P/I:P/A:P
affected versions
microsoft windows 10 1909 < 10.0.18363.1621; microsoft windows 10 2004 < 10.0.19041.1052; microsoft windows 10 20h2 < 10.0.19042.1052; and 3 more, listed in full below
also scored by
[email protected] 8.4 CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H · [email protected] 7.8 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

The CNA scored it 8.4 and NVD 4.6. Both are shown because both were published; we do not pick one.

check it yourself portal.msrc.microsoft.com receipt

Dated events

2021-06-15EPSS moved 0.02 to 0.182021-11-03Added to CISA KEV2021-11-17CISA remediation due2022-02-04EPSS moved 0.18 to 0.012026-06-15EPSS moved 0.17 to 0.07

Movement the material steps

9 Jun 20210.0184
15 Jun 20210.17642 · crossed 0.10
4 Feb 20220.01372 · crossed 0.10
7 Mar 20238.6e-4 · scoring model v2023.03.01
17 Mar 20250.10793 · crossed 0.10 · scoring model v2025.03.14
19 Mar 20250.23837
20 Mar 20250.1246
27 Mar 20250.24858
28 Mar 20250.13098
29 Mar 20250.24858
30 Mar 20250.13098
15 Jun 20260.06555 · crossed 0.10 · scoring model v2026.06.15

This score more than doubled inside 72 hours. Both observations are in the full history below.

Show all 46 observations
9 Jun 20210.0184
15 Jun 20210.17642
4 Feb 20220.01372
7 Mar 20238.6e-4
8 Mar 20230.00086
8 May 20230.00067
24 May 20230.00051
2 Aug 20230.00150
28 Sep 20230.00165
21 Nov 20230.00130
18 Dec 20230.00113
13 Jan 20240.00092
22 Feb 20240.00089
3 Apr 20240.00109
30 Apr 20240.00154
14 May 20240.00127
11 Jun 20240.00147
25 Jun 20240.00115
25 Jul 20240.00099
11 Oct 20240.00109
16 Dec 20240.00164
17 Dec 20240.00093
3 Jan 20250.00108
5 Feb 20250.00096
10 Mar 20250.00102
17 Mar 20250.10793
19 Mar 20250.23837
20 Mar 20250.1246
25 Mar 20250.13098
27 Mar 20250.24858
28 Mar 20250.13098
29 Mar 20250.24858
30 Mar 20250.13098
15 Apr 20250.11621
8 Jun 20250.12897
25 Jul 20250.14018
31 Aug 20250.11698
22 Oct 20250.15832
18 Nov 20250.17275
21 Nov 20250.15832
7 Dec 20250.20095
28 Jan 20260.19488
17 Mar 20260.18878
7 Apr 20260.18994
22 May 20260.16919
15 Jun 20260.06555

46 observations held. A highlighted step crossed a promotion threshold. A step marked with a scoring model moved because the instrument was replaced, not because the vulnerability changed. receipt

The full biography

EPSS 0.06555Published2021-06-08Public PoC2021-06-09CISA KEV2021-11-03Index as of2026-09-04

Listed by CISA 148 days after it published, exploit probability more than doubled between 2025-03-17 and 2025-03-19 (0.10793 → 0.23837) and the record had been public for 5 years, 2 months when this index was last written.

No material movement in 81 days as of the last ingest this index recorded.

Published 2021-06-08 receipt · Public PoC 2021-06-09 receipt · CISA KEV 2021-11-03 receipt · Index as of 2026-09-04 derived

Siblings and hubs

Records related to this one

Its defect family

microsoft windows 10 version 1909

Of the 15 records in this family, this is the only one with public proof-of-concept code, and it holds 2 references to it.

Grouped by shared product and weakness, not by shared vulnerability. Each record's own state is on its own page.

Family membership: computed, pro@dim2000

This record is one of a group, and the group's page describes all of them. This page is kept and dated, and the defect family's own page is the one we offer for indexing: the whole group.

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What usually comes next

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