vciy

CVE-2021-1732

INDEX BUILT · 2026-09-20

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Windows Win32k Elevation of Privilege Vulnerability

CVE-2021-17323 of 4 sources documented this
58

rank 58 = 40 + 12 + 0 + 0 + 6

rank@v1 · this cycle

Someone is already using it

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

EPSS 0.78376 · CISA KEV listed  ·  without this subject the record ranks 18

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 46

It is getting worse, not staying still

FIRST EPSS series, rescorings and bad loads removed

no persisting rise in 365 days  ·  without this subject the record ranks 58

How much of the world it touches

NVD CPE configurations

0 products in the CPE ranges  ·  without this subject the record ranks 58

Someone else already set the date

CISA KEV remediation due date

CISA remediation date held  ·  without this subject the record ranks 52

Unaudited dollar value2 of 3 inputs carry a receipt
Exposure$3.91Mover the next 30 days, if this record is yours
Movement-$50,100on 2026-04-20, the last material move, 4 months before this reading
Basisassumeda published average, not your estate

$3.91M = $4.99M incident cost x 1 exposure x 0.78376 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

0.78376EPSSKEV · LISTED
Severity7.8 HIGHreceipt
Harmtotal loss · ransomware-linkedreceipt
Exploitationransomware use knownreceipt
Defenseno fix version held
Movementdoubled within 72hreceipt
PLATEAU10Minimal movement since 2026-05-06, 121 days at 0.78, as of 2026-09-04. arc-rules@v1

Foresight · where to check next

Microsoft WindowsMicrosoft Windows1732

This record is one instance of CWE-787, out-of-bounds write. The index holds 14892 prior instances of this class, 163 KEV-listed. The nearest of its KEV-listed records are drawn beside this. taxonomy@v1

Full pattern panel

Prior records in this weakness class. Each is its own record, dated and receipted.
Color is a claim, not decoration:the hostile worldthe defenseno signalspoke length is how much of the record matches, not how bad it is

Sources disagree here.

Severity score
Microsoft7.8 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 1803? Check your version

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Harm, if it fires from the vector and the weakness

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Reachneeds local access · low privileges required · no user interaction · low attack complexityreceipt
ImpactComplete confidentiality, integrity and availability lossreceipt
Scored fromCVSS v3.1 · the CNA's vectorreceipt
Weakness classCWE-787 Out-of-bounds Writereceipt
Published consequencesCWE-787: Integrity: Modify Memory, Execute Unauthorized Code or Commands; Availability: DoS: Crash, Exit, or Restart; Other: Unexpected State[email protected]
Ransomware campaign useKnown (CISA)receipt

CISA KEV & Federal Remediation Deadline from the record and CISA

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

Fixed inNo fix version in held sources, as the index stood on 4 Sep 2026.
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 KEV251 daysderived

Exploit Status & Known PoCs a ladder, not a score

Current rung: Ransomware campaign use known, 2021-11-03.

  • RUNG 1Nothing observed in held sources
  • RUNG 2Proof-of-concept published · 11 public repositories2021-03-05receipt
  • RUNG 3Exploited in the wild · CISA KEV listed2021-11-03receipt
  • RUNG 4Ransomware campaign use known2021-11-03receipt

Authority who says so

CVSS, the CNA7.8 HIGHreceipt
CVSS, NVD4.6 MEDIUMreceipt
Exploit probability0.78376 · top 0.44% of all CVEsreceipt
Assigned bymicrosoftreceipt
Recorded changes72 · last 18 Sep 2026derived

Affected & Fixed Versions as published

Affected productMicrosoft Windows 10 Version 1803; Microsoft Windows 10 Version 1809; Microsoft Windows Server 2019; Microsoft Windows Server 2019 (Server Core installation); Microsoft Windows 10 Version 1909…receipt

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

Windows Win32k 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
weakness
CWE-787
also scored by
[email protected] 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H · [email protected] 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

The CNA scored it 7.8 and NVD 4.6. Both are shown because both were published; we do not pick one.

check it yourself portal.msrc.microsoft.com packetstormsecurity.com packetstormsecurity.com receipt

Dated events

2021-09-14EPSS moved 0.70 to 0.242021-11-03Added to CISA KEV2021-11-17CISA remediation due2025-03-17EPSS moved 0.04 to 0.902026-06-21EPSS moved 0.69 to 0.78

Movement the material steps

14 Apr 20210.70425
14 Sep 20210.24372 · crossed 0.50
16 Sep 20210.70425 · crossed 0.50
4 Feb 20220.09099 · crossed 0.10 and 0.50
7 Mar 20230.00395 · scoring model v2023.03.01
17 Mar 20250.89917 · crossed 0.10 and 0.50 · scoring model v2025.03.14
18 Mar 20250.90082 · crossed 0.90
29 Jun 20250.89602 · crossed 0.90
19 Jul 20250.901 · crossed 0.90
26 Aug 20250.8981 · crossed 0.90
17 Oct 20250.90278 · crossed 0.90
22 Oct 20250.89567 · crossed 0.90
3 Nov 20250.90251 · crossed 0.90
20 Apr 20260.89059 · crossed 0.90
15 Jun 20260.68965 · scoring model v2026.06.15
28 Aug 20260.78376

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

Show all 58 observations
14 Apr 20210.70425
14 Sep 20210.24372
16 Sep 20210.70425
4 Feb 20220.09099
26 Feb 20220.01405
1 Mar 20220.01413
7 Mar 20230.00395
8 May 20230.00473
1 Jun 20230.00448
17 Jun 20230.00569
8 Jul 20230.00725
2 Oct 20230.00769
11 Nov 20230.00684
7 Dec 20230.00685
22 Dec 20230.00970
30 Dec 20230.00876
4 Jan 20240.00436
29 Feb 20240.00570
14 Mar 20240.00436
30 Mar 20240.00497
13 Apr 20240.00350
14 May 20240.00296
30 Jun 20240.00298
15 Jul 20240.00305
4 Sep 20240.00431
17 Dec 20240.03209
30 Dec 20240.04537
16 Jan 20250.03498
1 Feb 20250.03392
4 Mar 20250.04122
17 Mar 20250.89917
18 Mar 20250.90082
20 Mar 20250.90321
23 Mar 20250.90515
29 Mar 20250.90601
17 Apr 20250.90515
27 Apr 20250.90601
18 Jun 20250.90515
29 Jun 20250.89602
19 Jul 20250.901
20 Jul 20250.90196
26 Aug 20250.8981
17 Oct 20250.90278
22 Oct 20250.89567
3 Nov 20250.90251
18 Nov 20250.90183
21 Nov 20250.90251
25 Nov 20250.90988
21 Jan 20260.90423
15 Mar 20260.90063
20 Apr 20260.89059
6 May 20260.87143
10 May 20260.88163
31 May 20260.88318
15 Jun 20260.68965
21 Jun 20260.78376
24 Jul 20260.77762
28 Aug 20260.78376

58 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 0.78376Published2021-02-25Public PoC2021-03-05CISA KEV2021-11-03Index as of2026-09-04

Listed by CISA 251 days after it published, exploit probability more than doubled between 2021-09-14 and 2021-09-16 (0.24372 → 0.70425) and the record had been public for 5 years, 6 months when this index was last written.

Published 2021-02-25 receipt · Public PoC 2021-03-05 receipt · CISA KEV 2021-11-03 receipt · Index as of 2026-09-04 derived

The pattern, elsewhere

This record is one instance of CWE-787, out-of-bounds write. The index holds 14892 prior instances of this class, 163 KEV-listed. The nearest of its KEV-listed records are drawn beside this. [email protected]

CVE-2024-30051 · Microsoft Windows 10 Version 1809matches 9 of 9KEV listed · 2024receipt
CVE-2023-23376 · Microsoft Windows 10 Version 1507matches 9 of 9KEV listed · 2023receipt
CVE-2023-28252 · Microsoft Windows 10 Version 1809matches 9 of 9KEV listed · 2023receipt
CVE-2022-24521 · Microsoft Windows 10 Version 1809matches 9 of 9KEV listed · 2022receipt
CVE-2022-37969 · Microsoft Windows 10 Version 1809matches 9 of 9KEV listed · 2022receipt
CVE-2022-41073 · Microsoft Windows 10 Version 1507matches 9 of 9KEV listed · 2022receipt

"Matches n of m" counts the attributes the two records can both be compared on: the CVSS metrics they share a version of, any weakness class beyond this one, and the vendor. fit-rules@v1

14892 records in this class held. The six above are drawn from the ones CISA has listed as exploited, ranked by how much of the record matches this one. That is why every one of them is KEV-listed: the pool is, so the colour on those spokes says nothing the pool has not already said.

No curated product neighbourhood is held for this product, so the records above are the nearest this index can name. The neighbourhood table covers a small set of products and is extended by hand.

Siblings and hubs

Records related to this one

Its defect family

microsoft windows 10 version 1803

Of the 6 records in this family, this is the only one with public proof-of-concept code, and it holds 11 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: held values

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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