vciy

CVE-2021-33781

INDEX BUILT · 2026-09-20

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Azure AD Security Feature Bypass Vulnerability

CVE-2021-337814 of 4 sources documented this
23

rank 23 = 1 + 14 + 1 + 7 + 0

rank@v1 · backlog

Someone is already using it

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

EPSS 0.02410  ·  without this subject the record ranks 22

What it costs you if it fires

NVD CVSS base score, then the CNA's own

CVSS 5.5, from NVD  ·  without this subject the record ranks 9

It is getting worse, not staying still

FIRST EPSS series, rescorings and bad loads removed

rose on 2026-04-23  ·  without this subject the record ranks 22

How much of the world it touches

NVD CPE configurations

7 products in the CPE ranges  ·  without this subject the record ranks 16

Someone else already set the date

CISA KEV remediation due date

no CISA due date  ·  without this subject the record ranks 23

Unaudited dollar value2 of 3 inputs carry a receipt
Exposure$106,000over the next 30 days, if this record is yours
Movement-$675,000on 2022-02-04, the last material move, 4 years, 6 months before this reading
Basisassumeda published average, not your estate

$106,000 = $4.99M incident cost x 0.8814887365328109 exposure x 0.0241 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

0.0241EPSSNOT IN KEVas of 2026-09-20
Severity8.1 HIGHreceipt
Harmpartial impactreceipt
Exploitationnone in held sources
Defensefix version namedreceipt
Movementdoubled within 72hreceipt
PLATEAU10Minimal movement since 2022-02-04, 1649 days at 0.02, as of 2026-08-11. 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
Microsoft8.1 HIGHreceipt
NVD5.5 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 1607? Check your version

A deterministic range check against the ranges this record publishes. It tells you where a version sits in the record, not whether your deployment is exploitable. No account needed.

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AcceptDeferPatch by…Not affectedMitigated

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Harm, if it fires from the vector and the weakness

Written for the ticket you're about to file.

Reachnetwork-reachable · low privileges required · no user interaction · low attack complexityreceipt
ImpactComplete confidentiality and integrity lossreceipt
Scored fromCVSS v3.1 · the CNA's vectorreceipt
Weakness classNo CWE mapping in held sources.

CISA KEV & Federal Remediation Deadline from the record and CISA

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

Fixed in10.0.14393.4704; 10.0.17763.2061; 10.0.18363.1679; 10.0.19041.1110; 10.0.19042.1110; 10.0.19043.1110; 10.0.22000.258receipt
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.

Exploit Status & Known PoCs a ladder, not a score

Current rung: Nothing observed in held sources.

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

Authority who says so

CVSS, the CNA8.1 HIGHreceipt
CVSS, NVD5.5 MEDIUMreceipt
Exploit probability0.0241 · top 17% of all CVEsreceipt
Blast breadth2 products across 1 vendorderived
Assigned bymicrosoftreceipt
Recorded changes34 · last 19 Sep 2026derived

Affected & Fixed Versions as published

Affected productMicrosoft Windows 10 Version 1607; Microsoft Windows 10 Version 1809; Microsoft Windows 10 Version 1909; Microsoft Windows 10 Version 2004; Microsoft Windows 10 Version 20H2…receipt
Published rangesmicrosoft windows 10 20h2; microsoft windows 10 21h1; microsoft windows 10 1809; microsoft windows 10 1909receipt
Show all 7 published ranges
microsoft windows 10 20h2
microsoft windows 10 21h1
microsoft windows 10 1809
microsoft windows 10 1909
microsoft windows 10 2004
microsoft windows server 2016 20h2
microsoft windows server 2016 2004
Fixed in10.0.14393.4704; 10.0.17763.2061; 10.0.18363.1679; 10.0.19041.1110; 10.0.19042.1110; 10.0.19043.1110; 10.0.22000.258receipt

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

Azure AD Security Feature Bypass Vulnerability receipt

NVD's analysis a second authority

severity
5.5 AV:N/AC:L/Au:S/C:P/I:P/A:N
affected versions
microsoft windows 10 20h2; microsoft windows 10 21h1; microsoft windows 10 1809; and 4 more, listed in full below
also scored by
[email protected] 8.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N · [email protected] 8.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

The CNA scored it 8.1 and NVD 5.5. Both are shown because both were published; we do not pick one.

check it yourself msrc.microsoft.com receipt

Dated events

2022-01-06EPSS moved 0.05 to 0.182022-02-04EPSS moved 0.18 to 0.022026-06-15EPSS moved 0.07 to 0.02

Movement the material steps

15 Jul 20210.00416
6 Jan 20220.17642 · crossed 0.10
4 Feb 20220.02288 · crossed 0.10
7 Mar 20230.00111 · scoring model v2023.03.01
17 Mar 20250.01633 · scoring model v2025.03.14
15 Jun 20260.02159 · scoring model v2026.06.15
11 Aug 20260.0241

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

Show all 34 observations
15 Jul 20210.00416
17 Jul 20210.04557
6 Jan 20220.17642
4 Feb 20220.02288
1 Apr 20220.0115
7 Mar 20230.00111
18 Apr 20230.00119
31 May 20230.00146
13 Jun 20230.00097
10 Aug 20230.00088
6 Oct 20230.00070
10 Jan 20240.00065
17 Dec 20240.00063
21 Jan 20250.00066
8 Feb 20250.00063
17 Mar 20250.01633
19 Mar 20250.01093
29 Mar 20250.0173
30 Mar 20250.01093
5 May 20250.01087
25 Jul 20250.01029
29 Jul 20250.00779
9 Aug 20250.00848
21 Oct 20250.00779
18 Nov 20250.00735
21 Nov 20250.00779
5 Dec 20250.01055
13 Apr 20260.02679
23 Apr 20260.06025
29 Apr 20260.05846
4 Jun 20260.07165
15 Jun 20260.02159
29 Jun 20260.02247
11 Aug 20260.0241

34 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 0.0241Published2021-07-14Index as of2026-08-11

Exploit probability more than doubled between 2021-07-15 and 2021-07-17 (0.00416 → 0.04557) and the record had been public for 5 years when this index was last written.

Published 2021-07-14 receipt · Index as of 2026-08-11 derived

Siblings and hubs

Records related to this one

Its defect family

microsoft windows

Of the 24 records in this family, this is the only one holding a stated fix version: 10.0.14393.4704; 10.0.17763.2061; 10.0.18363.1679; 10.0.1904.

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.

Browse the index from here

These are index-wide views, not findings about CVE-2021-33781.

What usually comes next

Everything above needs no account. What is below is work: assembling it, scoping it to your estate, watching it, and handing it to someone else.

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