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CVE-2021-41379

INDEX BUILT · 2026-09-20

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Windows Installer Elevation of Privilege Vulnerability

CVE-2021-413794 of 4 sources documented this
67

rank 67 = 40 + 12 + 0 + 9 + 6

rank@v1 · this cycle

Someone is already using it

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

EPSS 0.19532 · CISA KEV listed  ·  without this subject the record ranks 27

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 55

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 67

How much of the world it touches

NVD CPE configurations

15 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 61

Unaudited dollar value2 of 3 inputs carry a receipt
Exposure$597,000over the next 30 days, if this record is yours
Movement-$922,000on 2025-11-21, the last material move, 9 months before this reading
Basisassumeda published average, not your estate

$597,000 = $4.99M incident cost x 0.6121449559255632 exposure x 0.19532 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

0.19532EPSSKEV · LISTED
Severity5.5 MEDIUMreceipt
Harmpartial impact · ransomware-linkedreceipt
Exploitationransomware use knownreceipt
Defensefix version namedreceipt
Movementdoubled within 72hreceipt
PLATEAU10Minimal movement since 2026-06-15, 87 days at 0.20, as of 2026-09-10. arc-rules@v1

Foresight · where to check next

Microsoft WindowsMicrosoft WindowsMicrosoft WindowsMicrosoft WindowsMicrosoft Windows41379

This record is one instance of CWE-59, improper link resolution before file access ('link following'). The index holds 1732 prior instances of this class, 24 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
Microsoft5.5 MEDIUMreceipt
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 1507? 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 availability lossreceipt
Scored fromCVSS v3.1 · the CNA's vectorreceipt
Weakness classCWE-59 Improper Link Resolution Before File Access ('Link Following')receipt
Published consequencesCWE-59: Confidentiality, Integrity, Access Control: Read Files or Directories, Modify Files or Directories, Bypass Protection Mechanism; Other: Execute Unauthorized Code or Commands[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 in10.0.10240.19119; 10.0.14393.4770; 10.0.17763.2300; 10.0.18363.1916; 10.0.19041.1348; 10.0.19042.1348; 10.0.19043.1348; 10.0.22000.318; 6.1.7601.25769…receipt
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 2022-03-17receipt
CISA required actionApply updates per vendor instructions.receipt
Published to CISA KEV113 daysderived

Exploit Status & Known PoCs a ladder, not a score

Current rung: Ransomware campaign use known, 2022-03-03.

  • RUNG 1Nothing observed in held sources
  • RUNG 2Proof-of-concept published
  • RUNG 3Exploited in the wild · CISA KEV listed2022-03-03receipt
  • RUNG 4Ransomware campaign use known2022-03-03receipt

Authority who says so

CVSS, the CNA5.5 MEDIUMreceipt
CVSS, NVD4.6 MEDIUMreceipt
Exploit probability0.19532 · top 3% of all CVEsreceipt
Blast breadth3 products across 1 vendorderived
Assigned bymicrosoftreceipt
Recorded changes92 · last 19 Sep 2026derived

Affected & Fixed Versions as published

Affected productMicrosoft Windows 10 Version 1507; Microsoft Windows 10 Version 1607; Microsoft Windows 10 Version 1809; Microsoft Windows 10 Version 1909; Microsoft Windows 10 Version 2004…receipt
Published rangesmicrosoft windows 10 1507 < 10.0.10240.19119; microsoft windows 10 1607 < 10.0.14393.4770; microsoft windows 10 1809 < 10.0.17763.2300; microsoft windows 10 1909 < 10.0.18363.1916receipt
Show all 15 published ranges
microsoft windows 10 1507 < 10.0.10240.19119
microsoft windows 10 1607 < 10.0.14393.4770
microsoft windows 10 1809 < 10.0.17763.2300
microsoft windows 10 1909 < 10.0.18363.1916
microsoft windows 10 2004 < 10.0.19041.1348
microsoft windows 10 20h2 < 10.0.19042.1348
microsoft windows 10 21h1 < 10.0.19043.1348
microsoft windows 11 21h2 < 10.0.22000.318
microsoft windows server 2004 < 10.0.19041.1348
microsoft windows server 2008 r2
microsoft windows server 2012 r2
microsoft windows server 2016 < 10.0.14393.4770
microsoft windows server 2019 < 10.0.17763.2300
microsoft windows server 2022 < 10.0.20348.350
microsoft windows server 20h2 < 10.0.19042.1348
Fixed in10.0.10240.19119; 10.0.14393.4770; 10.0.17763.2300; 10.0.18363.1916; 10.0.19041.1348; 10.0.19042.1348; 10.0.19043.1348; 10.0.22000.318; 6.1.7601.25769…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 Installer 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-59
affected versions
microsoft windows 10 1507 < 10.0.10240.19119; microsoft windows 10 1607 < 10.0.14393.4770; microsoft windows 10 1809 < 10.0.17763.2300; and 12 more, listed in full below
also scored by
[email protected] 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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 5.5 and NVD 4.6. Both are shown because both were published; we do not pick one.

check it yourself msrc.microsoft.com receipt

Dated events

2021-11-13EPSS moved 0.01 to 0.072022-03-03Added to CISA KEV2022-03-17CISA remediation due2023-03-07EPSS moved 0.01 to 0.962026-06-15EPSS moved 0.01 to 0.20

Movement the material steps

10 Nov 20210.00416
18 Dec 20210.24372 · crossed 0.10
4 Feb 20220.01405 · crossed 0.10
7 Mar 20230.95635 · crossed 0.10 and 0.50 and 0.90 · scoring model v2023.03.01
2 Jun 20230.89010 · crossed 0.90
30 Jul 20230.75458
29 Aug 20230.64305
29 Dec 20230.02073 · crossed 0.10 and 0.50
17 Mar 20250.0351 · scoring model v2025.03.14
18 Nov 20250.31527 · crossed 0.10
21 Nov 20250.01335 · crossed 0.10
15 Jun 20260.20255 · crossed 0.10 · scoring model v2026.06.15
10 Sep 20260.19532

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

Show all 81 observations
10 Nov 20210.00416
12 Nov 20210.00624
13 Nov 20210.06701
18 Dec 20210.24372
4 Feb 20220.01405
7 Mar 20230.95635
13 Mar 20230.95553
26 Mar 20230.91639
2 Jun 20230.89010
1 Jul 20230.80015
30 Jul 20230.75458
29 Aug 20230.64305
25 Oct 20230.58924
29 Dec 20230.02073
14 Feb 20240.01611
13 Mar 20240.01141
11 Apr 20240.00581
21 May 20240.00410
16 Jun 20240.00376
30 Jun 20240.00445
25 Jul 20240.00321
26 Jul 20240.00343
9 Aug 20240.00420
21 Aug 20240.00296
5 Sep 20240.01682
18 Sep 20240.00319
2 Oct 20240.00880
16 Oct 20240.00452
13 Nov 20240.00672
27 Nov 20240.00337
13 Dec 20240.00578
17 Dec 20240.00268
27 Dec 20240.00165
11 Jan 20250.00180
27 Jan 20250.00130
15 Mar 20250.00143
17 Mar 20250.0351
19 Mar 20250.04634
29 Mar 20250.01531
30 Mar 20250.04634
15 May 20250.0664
17 May 20250.04634
22 May 20250.04636
4 Jun 20250.04634
8 Jun 20250.04761
18 Jun 20250.04764
1 Jul 20250.04761
8 Jul 20250.04121
16 Aug 20250.04124
21 Aug 20250.04121
1 Oct 20250.03791
22 Oct 20250.03319
27 Oct 20250.0361
28 Oct 20250.03319
31 Oct 20250.01148
6 Nov 20250.01335
18 Nov 20250.31527
21 Nov 20250.01335
9 Dec 20250.01953
11 Dec 20250.01335
16 Dec 20250.01336
18 Dec 20250.01573
19 Dec 20250.0135
27 Dec 20250.01424
28 Dec 20250.0133
30 Dec 20250.01316
31 Dec 20250.01656
1 Jan 20260.01717
6 Jan 20260.01716
2 Feb 20260.01131
21 Feb 20260.0116
26 Feb 20260.01159
25 Apr 20260.01177
6 May 20260.01159
7 May 20260.01181
14 May 20260.01348
29 May 20260.01021
15 Jun 20260.20255
4 Jul 20260.20099
20 Aug 20260.19381
10 Sep 20260.19532

81 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 0.19532Published2021-11-10CISA KEV2022-03-03Index as of2026-09-10

Listed by CISA 113 days after it published, exploit probability more than doubled between 2021-11-12 and 2021-11-13 (0.00624 → 0.06701) and the record had been public for 4 years, 10 months when this index was last written.

Published 2021-11-10 receipt · CISA KEV 2022-03-03 receipt · Index as of 2026-09-10 derived

The pattern, elsewhere

This record is one instance of CWE-59, improper link resolution before file access ('link following'). The index holds 1732 prior instances of this class, 24 KEV-listed. The nearest of its KEV-listed records are drawn beside this. [email protected]

CVE-2025-21391 · Microsoft Windows 10 Version 1507matches 8 of 9KEV listed · 2025receipt
CVE-2025-60710 · Microsoft Windows 11 Version 24H2matches 7 of 9KEV listed · 2025receipt
CVE-2022-21999 · Microsoft Windows 10 Version 1809matches 7 of 9KEV listed · 2022receipt
CVE-2020-0638 · Microsoft Windowsmatches 7 of 9KEV listed · 2020receipt
CVE-2019-0841 · Microsoft Windowsmatches 7 of 9KEV listed · 2019receipt
CVE-2019-1064 · Microsoft Windows 10 Version 1703matches 7 of 9KEV listed · 2019receipt

"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

1732 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.

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