vciy

CVE-2023-21819

INDEX BUILT · 2026-09-20

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Windows Secure Channel Denial of Service Vulnerability

CVE-2023-218194 of 4 sources documented this
34

rank 34 = 8 + 19 + 1 + 6 + 0

rank@v1 · scheduled

Someone is already using it

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

EPSS 0.30806  ·  without this subject the record ranks 26

What it costs you if it fires

NVD CVSS base score, then the CNA's own

CVSS 7.5, from the CNA  ·  without this subject the record ranks 15

It is getting worse, not staying still

FIRST EPSS series, rescorings and bad loads removed

rose on 2026-02-16  ·  without this subject the record ranks 33

How much of the world it touches

NVD CPE configurations

5 products in the CPE ranges  ·  without this subject the record ranks 28

Someone else already set the date

CISA KEV remediation due date

no CISA due date  ·  without this subject the record ranks 34

Unaudited dollar value2 of 3 inputs carry a receipt
Exposure$941,000over the next 30 days, if this record is yours
Movement-$480,000on 2025-03-30, the last material move, 1 year, 2 months before this reading
Basisassumeda published average, not your estate

$941,000 = $4.99M incident cost x 0.6121449559255632 exposure x 0.30806 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

0.30806EPSSNOT IN KEVas of 2026-09-20
Severity7.5 HIGHreceipt
Harmunauthenticated · networkreceipt
Exploitationnone in held sources
Defensefix version namedreceipt
Movementscoring model changedreceipt
PLATEAU10Minimal movement since 2025-11-21, 206 days at 0.31, as of 2026-06-15. arc-rules@v1

Foresight · where to check next

CVE-2016-4523CVE-2014-0160CVE-2020-11899CVE-2016-1646Google ChromeMicrosoft Windows21819

This record is one instance of CWE-125, out-of-bounds read. The index holds 9767 prior instances of this class, 19 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

Running Microsoft Windows 10 Version 1809? 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.

Watch this record

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Harm, if it fires from the vector and the weakness

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Reachnetwork-reachable · no privileges required · no user interaction · low attack complexityreceipt
ImpactComplete availability lossreceipt
Scored fromCVSS v3.1 · the CNA's vectorreceipt
Weakness classCWE-125 Out-of-bounds Readreceipt
Published consequencesCWE-125: Confidentiality: Read Memory; Confidentiality: Bypass Protection Mechanism; Availability: DoS: Crash, Exit, or Restart; Other: Varies by Context[email protected]

CISA KEV & Federal Remediation Deadline from the record and CISA

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

Fixed in10.0.17763.4010; 10.0.19042.2604; 10.0.19044.2604; 10.0.19045.2604; 10.0.22621.1574; 10.0.20348.1547receipt
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 CNA7.5 HIGHreceipt
Exploit probability0.30806 · top 2% of all CVEsreceipt
Blast breadth1 product across 1 vendorderived
Assigned bymicrosoftreceipt
Recorded changes36 · last 19 Sep 2026derived

Affected & Fixed Versions as published

Affected productMicrosoft Windows 10 Version 1809; Microsoft Windows 10 Version 20H2; Microsoft Windows 10 Version 21H2; Microsoft Windows 10 Version 22H2; Microsoft Windows 11 version 21H2…receipt
Published rangesmicrosoft windows 10 1809 < 10.0.17763.4010; microsoft windows 10 20h2 < 10.0.19042.2604; microsoft windows 10 21h2 < 10.0.19044.2604; microsoft windows 10 22h2 < 10.0.19045.2604receipt
Show all 5 published ranges
microsoft windows 10 1809 < 10.0.17763.4010
microsoft windows 10 20h2 < 10.0.19042.2604
microsoft windows 10 21h2 < 10.0.19044.2604
microsoft windows 10 22h2 < 10.0.19045.2604
microsoft windows 11 21h2 < 10.0.22000.1574
Fixed in10.0.17763.4010; 10.0.19042.2604; 10.0.19044.2604; 10.0.19045.2604; 10.0.22621.1574; 10.0.20348.1547receipt

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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Attack path

Unauthenticated network requestno credentials, no interactionMicrosoft Windows Server 2019CWE-125 out-of-bounds readAvailability lossA:Hexploits CWE-125data compromise

What it is stated by the CNA

Windows Secure Channel Denial of Service Vulnerability receipt

NVD's analysis a second authority

weakness
CWE-125
affected versions
microsoft windows 10 1809 < 10.0.17763.4010; microsoft windows 10 20h2 < 10.0.19042.2604; microsoft windows 10 21h2 < 10.0.19044.2604; and 2 more, listed in full below
also scored by
[email protected] 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

check it yourself msrc.microsoft.com receipt

Dated events

2025-03-17EPSS moved 0.00 to 0.072025-03-25EPSS moved 0.16 to 0.372026-06-15EPSS moved 0.21 to 0.31

Movement the material steps

15 Feb 20230.00885
7 Mar 20237.6e-4 · scoring model v2023.03.01
17 Mar 20250.06596 · scoring model v2025.03.14
19 Mar 20250.16047 · crossed 0.10
25 Mar 20250.37187
29 Mar 20250.52911 · crossed 0.50
30 Mar 20250.37187 · crossed 0.50
18 Nov 20250.16192
21 Nov 20250.33656
24 Feb 20260.21377
15 Jun 20260.30806 · scoring model v2026.06.15

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

Show all 36 observations
15 Feb 20230.00885
24 Feb 20230.02251
7 Mar 20237.6e-4
8 Mar 20230.00076
21 Apr 20230.00136
29 Apr 20230.00140
8 May 20230.00120
26 Jun 20230.00129
8 Jul 20230.00168
20 Jul 20230.00179
7 Aug 20230.00126
10 Sep 20230.00090
18 Nov 20230.00065
11 Dec 20230.00063
21 Feb 20240.00109
29 May 20240.00077
30 Jun 20240.00110
27 Jul 20240.00121
9 Aug 20240.00087
6 Sep 20240.00090
17 Dec 20240.00060
17 Mar 20250.06596
19 Mar 20250.16047
25 Mar 20250.37187
29 Mar 20250.52911
30 Mar 20250.37187
25 Sep 20250.33656
18 Nov 20250.16192
21 Nov 20250.33656
11 Dec 20250.34974
16 Feb 20260.38372
17 Feb 20260.39189
18 Feb 20260.33178
21 Feb 20260.30657
24 Feb 20260.21377
15 Jun 20260.30806

36 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 0.30806Published2023-02-14Index as of2026-06-15

Exploit probability more than doubled between 2025-03-17 and 2025-03-19 (0.06596 → 0.16047) and the record had been public for 3 years, 4 months when this index was last written.

Published 2023-02-14 receipt · Index as of 2026-06-15 derived

The pattern, elsewhere

This record is one instance of CWE-125, out-of-bounds read. The index holds 9767 prior instances of this class, 19 KEV-listed. The nearest of its KEV-listed records are drawn beside this. [email protected]

CVE-2016-4523matches 8 of 8KEV listed · 2016receipt
CVE-2014-0160matches 6 of 8KEV listed · 2014receipt
CVE-2020-11899matches 5 of 8KEV listed · 2020receipt
CVE-2016-1646matches 5 of 8KEV listed · 2016receipt
CVE-2026-11645 · Google Chromematches 5 of 9KEV listed · 2026receipt
CVE-2025-24991 · Microsoft Windows 10 Version 1507matches 5 of 9KEV listed · 2025receipt

"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

9767 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

Browse the index from here

These are index-wide views, not findings about CVE-2023-21819.

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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