CASCACascade Atlas

Evidence dossier

CVE-2021-28310

Win32k Elevation of Privilege Vulnerability

Exploited in the wild (CISA KEV since Nov 3, 2021). microsoft reports CVSS 3.1 7.8. EPSS estimates 8.3% exploit likelihood as of Aug 27, 2026.

71.4–75.8Priority evidence range
Evidence current through Aug 27, 2026, 6:09 PM UTC

As of Aug 27, 2026

Normalized restatement

Win32k Elevation of Privilege Vulnerability

State
PUBLISHED
Published
Apr 13, 2021
Updated
Oct 21, 2025
Evidence coverage
92%

Evidence chronology

What was known when

Download this view's receipt →
  1. Source dateSource date omittedFirst observed by CASCA
    CISA-ADP

    Record text: CISA ADP Vulnrichment

    Inspect raw assertion
    Field
    container
    Value
    CISA ADP Vulnrichment
    Original evidence ↗
  2. Source dateSource date omittedFirst observed by CASCA
    CVE Program

    Record text: CVE Program Container

    Inspect raw assertion
    Field
    container
    Value
    CVE Program Container
    Original evidence ↗
  3. Source dateSource date omittedFirst observed by CASCA
    microsoft

    Record text: Win32k Elevation of Privilege Vulnerability

    Inspect raw assertion
    Field
    container
    Value
    Win32k Elevation of Privilege Vulnerability
    Original evidence ↗
  4. Source dateFirst observed by CASCA
    CISA KEV

    Exploitation cataloged: Microsoft Win32k Privilege Escalation Vulnerability

    Inspect raw assertion
    Field
    observed_exploitation
    Value
    Microsoft Win32k Privilege Escalation Vulnerability
    Original evidence ↗
  5. Source dateFirst observed by CASCA
    FIRST EPSS

    EPSS score: 8.33% probability · 94.53th percentile

    Inspect raw assertion
    Field
    model_probability
    Value
    Probability 0.083300000000; percentile 0.945260000000
    Original evidence ↗
ExploitationCatalog member

CISA KEV · catalog date Nov 3, 2021 · first observed Jul 19, 2026

Exploit likelihood8.33%

FIRST EPSS · score date Aug 27, 2026 · 94.5th percentile · first observed Aug 27, 2026

SeverityCVSS 7.8

microsoft · CVSS 3.1 · first observed Jul 19, 2026 · same-version scores align in this snapshot

Evidence detail

Source limits and decisions

Why each evidence state has this value

casca-unknown-reasons-v1
Exploitation statusEvidence supported

Eligible evidence is present for this bounded claim.

Revision
evidence-policy-v1.1.0
Cutoff
Aug 27, 2026
Resolution
None
Exploit likelihoodEvidence supported

Eligible evidence is present for this bounded claim.

Revision
evidence-policy-v1.1.0
Cutoff
Aug 27, 2026
Resolution
None
Severity assessmentEvidence supported

Eligible evidence is present for this bounded claim.

Revision
casca-direct-cvss-eligibility-v1
Cutoff
Aug 27, 2026
Resolution
None
Affected productsSource-reported scope

The cited source assertion is retained while canonical product linkage remains open.

Revision
casca-factor-d-obligations-v1
Cutoff
Aug 27, 2026
Resolution
Resolve identity

Source comparison

Who said what

CISA-ADPIndependent enrichment
Record text

CISA ADP Vulnrichment

Inspect raw assertion
Field
container
Value
CISA ADP Vulnrichment
Source dateSource date omittedFirst observed by CASCAOriginal evidence ↗
CVE ProgramDerivative copy
Record text

CVE Program Container

Inspect raw assertion
Field
container
Value
CVE Program Container
Source dateSource date omittedFirst observed by CASCAOriginal evidence ↗
microsoftOriginal assertion
Record text

Win32k Elevation of Privilege Vulnerability

Inspect raw assertion
Field
container
Value
Win32k Elevation of Privilege Vulnerability
Source dateSource date omittedFirst observed by CASCAOriginal evidence ↗
CISA KEVOriginal assertion
Exploitation cataloged

Microsoft Win32k Privilege Escalation Vulnerability

Inspect raw assertion
Field
observed_exploitation
Value
Microsoft Win32k Privilege Escalation Vulnerability
Source dateFirst observed by CASCAOriginal evidence ↗
FIRST EPSSOriginal assertion
EPSS score

8.33% probability · 94.53th percentile

Inspect raw assertion
Field
model_probability
Value
Probability 0.083300000000; percentile 0.945260000000
Source dateFirst observed by CASCAOriginal evidence ↗

Applicability

Cited product scope

Trace impact →
9Underlying assertions
9Canonical products
9Target assertions
0Constraint assertions

Grouped from 1 configuration nodes in this exact snapshot. Visual grouping is navigational; asset exposure and root cause require cited evidence.

Identity source boundaries
  • Cpe dictionary1,775,266 records · observed through 2026-07-21T06:45:29.809Z27d65b0f-b718-4b4f-bb79-c47c68d09dfa
  • Cpe match643,502 records · observed through 2026-07-21T08:13:17.697Z955dae73-7302-438b-aee1-058d7cc5d48e

19 scope groups

microsoft · source assertedMicrosoftWindows 10 Version 1803Direct source scope
Affected: 10.0.0 to before publication (custom comparison)
Source-reported scope

Canonical linkage remains open; the cited source assertion is retained below.

Inspect raw assertion[{"status": "affected", "version": "10.0.0", "lessThan": "publication", "versionType": "custom"}]
microsoft · source assertedMicrosoftWindows 10 Version 1809Direct source scope
Affected: 10.0.0 to before publication (custom comparison)
Source-reported scope

Canonical linkage remains open; the cited source assertion is retained below.

Inspect raw assertion[{"status": "affected", "version": "10.0.0", "lessThan": "publication", "versionType": "custom"}]
microsoft · source assertedMicrosoftWindows 10 Version 1909Direct source scope
Affected: 10.0.0 to before publication (custom comparison)
Source-reported scope

Canonical linkage remains open; the cited source assertion is retained below.

Inspect raw assertion[{"status": "affected", "version": "10.0.0", "lessThan": "publication", "versionType": "custom"}]
microsoft · source assertedMicrosoftWindows 10 Version 2004Direct source scope
Affected: 10.0.0 to before publication (custom comparison)
Source-reported scope

Canonical linkage remains open; the cited source assertion is retained below.

Inspect raw assertion[{"status": "affected", "version": "10.0.0", "lessThan": "publication", "versionType": "custom"}]
microsoft · source assertedMicrosoftWindows 10 Version 20H2Direct source scope
Affected: 10.0.0 to before publication (custom comparison)
Source-reported scope

Canonical linkage remains open; the cited source assertion is retained below.

Inspect raw assertion[{"status": "affected", "version": "10.0.0", "lessThan": "publication", "versionType": "custom"}]
microsoft · source assertedMicrosoftWindows Server 2019Direct source scope
Affected: 10.0.0 to before publication (custom comparison)
Source-reported scope

Canonical linkage remains open; the cited source assertion is retained below.

Inspect raw assertion[{"status": "affected", "version": "10.0.0", "lessThan": "publication", "versionType": "custom"}]
microsoft · source assertedMicrosoftWindows Server 2019 (Server Core installation)Direct source scope
Affected: 10.0.0 to before publication (custom comparison)
Source-reported scope

Canonical linkage remains open; the cited source assertion is retained below.

Inspect raw assertion[{"status": "affected", "version": "10.0.0", "lessThan": "publication", "versionType": "custom"}]
microsoft · source assertedMicrosoftWindows Server, version 1909 (Server Core installation)Direct source scope
Affected: 10.0.0 to before publication (custom comparison)
Source-reported scope

Canonical linkage remains open; the cited source assertion is retained below.

Inspect raw assertion[{"status": "affected", "version": "10.0.0", "lessThan": "publication", "versionType": "custom"}]
microsoft · source assertedMicrosoftWindows Server version 2004Direct source scope
Affected: 10.0.0 to before publication (custom comparison)
Source-reported scope

Canonical linkage remains open; the cited source assertion is retained below.

Inspect raw assertion[{"status": "affected", "version": "10.0.0", "lessThan": "publication", "versionType": "custom"}]
microsoft · source assertedMicrosoftWindows Server version 20H2Direct source scope
Affected: 10.0.0 to before publication (custom comparison)
Source-reported scope

Canonical linkage remains open; the cited source assertion is retained below.

Inspect raw assertion[{"status": "affected", "version": "10.0.0", "lessThan": "publication", "versionType": "custom"}]
NVD CPE · OPERATING SYSTEMmicrosoftwindows_10_1803Vulnerable target · 1 assertions
Version not applicableCanonical identity product-5e821ea3746af154a469c180e78b9f4d663edf21461517987eed76740c7910c1Linked exact
Scope supported
Inspect raw assertion
  1. cpe:2.3:o:microsoft:windows_10_1803:-:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 0
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    00345596-e9e0-4096-8dc6-0212f4747a13
NVD CPE · OPERATING SYSTEMmicrosoftwindows_10_1809Vulnerable target · 1 assertions
Version not applicableCanonical identity product-a3084138383423221f61594e86f5b295e5e254acd7ae5284f45e0877a084db43Linked exact
Scope supported
Inspect raw assertion
  1. cpe:2.3:o:microsoft:windows_10_1809:-:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 1
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    2e332666-2e03-468e-bc30-299816d6e8ed
NVD CPE · OPERATING SYSTEMmicrosoftwindows_10_1909Vulnerable target · 1 assertions
Version not applicableCanonical identity product-ef5324dcc791e4e872d6c2be0aefa1d7687ca82c3b4ac5d1f72c76cce8395218Linked exact
Scope supported
Inspect raw assertion
  1. cpe:2.3:o:microsoft:windows_10_1909:-:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 2
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    a1b570a8-ed1a-46b6-b8ab-064445f8fc4c
NVD CPE · OPERATING SYSTEMmicrosoftwindows_10_2004Vulnerable target · 1 assertions
Version not applicableCanonical identity product-9b245936275be71b526838fc72ea633d195b35bdd9dfc31bb6df51e7700edeccLinked exact
Scope supported
Inspect raw assertion
  1. cpe:2.3:o:microsoft:windows_10_2004:-:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 3
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    d4dbe5b2-ae10-4251-bcda-dc5edee6ee67
NVD CPE · OPERATING SYSTEMmicrosoftwindows_10_20h2Vulnerable target · 1 assertions
Version not applicableCanonical identity product-55e90faed8848f3d316cf702d119e83086b6dc5a963d9947a7df1c589f50346dLinked exact
Scope supported
Inspect raw assertion
  1. cpe:2.3:o:microsoft:windows_10_20h2:-:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 4
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    6afd13a6-a390-4400-9029-2f4058ca17e2
NVD CPE · OPERATING SYSTEMmicrosoftwindows_server_1909Vulnerable target · 1 assertions
Version not applicableCanonical identity product-11ee14cb5467893e953fd2afd492aa2a80b330b2831c4c10e31a6d9476b8f7abLinked exact
Scope supported
Inspect raw assertion
  1. cpe:2.3:o:microsoft:windows_server_1909:-:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 5
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    ade7e7b1-64ac-4986-a50b-0918a42c05bb
NVD CPE · OPERATING SYSTEMmicrosoftwindows_server_2004Vulnerable target · 1 assertions
Version not applicableCanonical identity product-571f6df0fa50d71be9551414060ed8bfcdb500437871cf9595b7fa6b034cecbdLinked exact
Scope supported
Inspect raw assertion
  1. cpe:2.3:o:microsoft:windows_server_2004:-:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 6
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    62224791-644c-4d1f-ad77-56b16cf27630
NVD CPE · OPERATING SYSTEMmicrosoftwindows_server_2019Vulnerable target · 1 assertions
Version not applicableCanonical identity product-25a2932c0bbcb648f7e391c8b9d34c734e5085444c03c1c206b9d4c4baa80b25Linked exact
Scope supported
Inspect raw assertion
  1. cpe:2.3:o:microsoft:windows_server_2019:-:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 7
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    db79ee26-fc32-417d-a49c-a1a63165a968
NVD CPE · OPERATING SYSTEMmicrosoftwindows_server_20h2Vulnerable target · 1 assertions
Version not applicableCanonical identity product-457c0c3b89fb1cf896e8491223eac8b0cb1ea61ce3174f915e4fe1032759d5a2Linked exact
Scope supported
Inspect raw assertion
  1. cpe:2.3:o:microsoft:windows_server_20h2:-:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 8
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    84f9b6b1-4fee-4d4b-b35f-b07822ccd669

Affected-product evidence

Accepted scope and product mapping

9 canonical links · 1 source-reported links

Mapping establishedEvidence supported

vendor-01299a5a765aea70faa05f2d06e0c26a5d498fd34553e868d89e8a43b31864db · product-11ee14cb5467893e953fd2afd492aa2a80b330b2831c4c10e31a6d9476b8f7ab

Source class
Nvd cpe vulnerable target
Assertions
1
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Aug 27, 2026
Retained assertion IDs
a4e4eb22-9e1c-4f5a-8495-abcc11873245
Mapping establishedEvidence supported

vendor-01299a5a765aea70faa05f2d06e0c26a5d498fd34553e868d89e8a43b31864db · product-25a2932c0bbcb648f7e391c8b9d34c734e5085444c03c1c206b9d4c4baa80b25

Source class
Nvd cpe vulnerable target
Assertions
1
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Aug 27, 2026
Retained assertion IDs
3aabbbfd-6f61-4d5f-a057-a0c8ed6db046
Mapping establishedEvidence supported

vendor-01299a5a765aea70faa05f2d06e0c26a5d498fd34553e868d89e8a43b31864db · product-457c0c3b89fb1cf896e8491223eac8b0cb1ea61ce3174f915e4fe1032759d5a2

Source class
Nvd cpe vulnerable target
Assertions
1
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Aug 27, 2026
Retained assertion IDs
53deaa6d-018c-41fb-9d3e-bb25fbffdff7
Mapping establishedEvidence supported

vendor-01299a5a765aea70faa05f2d06e0c26a5d498fd34553e868d89e8a43b31864db · product-55e90faed8848f3d316cf702d119e83086b6dc5a963d9947a7df1c589f50346d

Source class
Nvd cpe vulnerable target
Assertions
1
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Aug 27, 2026
Retained assertion IDs
a15528a6-7da5-43c0-9736-6a6ff3601067
Mapping establishedEvidence supported

vendor-01299a5a765aea70faa05f2d06e0c26a5d498fd34553e868d89e8a43b31864db · product-571f6df0fa50d71be9551414060ed8bfcdb500437871cf9595b7fa6b034cecbd

Source class
Nvd cpe vulnerable target
Assertions
1
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Aug 27, 2026
Retained assertion IDs
1fe24c48-c330-4820-b70a-e73ccc12312e
Mapping establishedEvidence supported

vendor-01299a5a765aea70faa05f2d06e0c26a5d498fd34553e868d89e8a43b31864db · product-5e821ea3746af154a469c180e78b9f4d663edf21461517987eed76740c7910c1

Source class
Nvd cpe vulnerable target
Assertions
1
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Aug 27, 2026
Retained assertion IDs
120cc380-c145-47d4-b370-cf147bf0307a
Mapping establishedEvidence supported

vendor-01299a5a765aea70faa05f2d06e0c26a5d498fd34553e868d89e8a43b31864db · product-9b245936275be71b526838fc72ea633d195b35bdd9dfc31bb6df51e7700edecc

Source class
Nvd cpe vulnerable target
Assertions
1
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Aug 27, 2026
Retained assertion IDs
ba7f8751-2964-461d-a8e8-83265ff4943d
Mapping establishedEvidence supported

vendor-01299a5a765aea70faa05f2d06e0c26a5d498fd34553e868d89e8a43b31864db · product-a3084138383423221f61594e86f5b295e5e254acd7ae5284f45e0877a084db43

Source class
Nvd cpe vulnerable target
Assertions
1
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Aug 27, 2026
Retained assertion IDs
cc048def-65f9-4f89-8288-d259e0d2075a
Mapping establishedEvidence supported

vendor-01299a5a765aea70faa05f2d06e0c26a5d498fd34553e868d89e8a43b31864db · product-ef5324dcc791e4e872d6c2be0aefa1d7687ca82c3b4ac5d1f72c76cce8395218

Source class
Nvd cpe vulnerable target
Assertions
1
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Aug 27, 2026
Retained assertion IDs
1125dfe9-e499-4589-91cf-49f3eee1e910
Source-reported scopeSource-reported scope

Canonical linkage remains open; the cited source assertion is retained below.

Vendor specified only by source · Product specified only by source

Source class
Direct cve affected
Assertions
10
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Aug 27, 2026
Retained assertion IDs
20646ad9-0cca-48cb-8165-54cc1d0d7ab06f7f7510-2660-4f8b-8c9c-0bb3a1d0371a75a6244f-e7ff-4353-ad05-f0b7c4d0ce9d76e4fb5b-e9e5-400c-99c7-9da930459e269836f28a-e368-4d92-a4ae-27e40b2142a49bfbd295-3ec5-46ea-979c-47fe5463584fa4862cb6-ca3c-4132-bf91-6e6b98a37671ac3f4982-d3b5-490d-a72e-037b3be27f02c5e091e1-396d-469f-b333-5683401d9071dbc41f9d-4da9-4307-adbf-471f3c2d377e

Assessments

CVSS by origin

4.6
NVDCVSS 2.0 · role Primary · priority eligiblevalid_matchAV:L/AC:L/Au:N/C:P/I:P/A:P
7.8
NVDCVSS 3.1 · role Secondary · priority eligiblevalid_matchCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.8
secure@microsoft.comCVSS 3.1 · role Secondary · priority eligiblevalid_matchCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.8
microsoftCVSS 3.1 · role unknown · display onlyDirect record assessment retained outside normalized eligibilityCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C

Direct CVE/CNA normalized decisions

7.8Priority eligible

microsoft

CVSS 3.1 · Primary · Original assertion · rank 1

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C
Validation
Valid match
Recomputed
7.8
Decision reason
Evidence supported
Policy
casca-direct-cvss-eligibility-v1

Assessments are retained side by side under closed precedence. Cascade never averages CVSS.

Evidence boundaries

  • KEV membership is authoritative for the catalog, not proof of exposure in any environment.
  • EPSS is a dated model probability and not an individual-environment prediction.
  • Affected or fixed status applies only to the exact cited product and version scope; remaining scope stays source-scoped.
  • NVD-carried upstream facts remain derivative; independent corroboration requires a separately authored source.
  • Only NVD metrics validated under the generation-bound calculator are Public Priority eligible; direct CVE record metrics remain display-only.
  • NVD CVSS source eligibility is closed: NVD-authored, exact record-source, or registered same-CVE container origin; unmapped sources remain display-only.
  • Core replay supports the active and immediately prior generation; retrospective valid-at replay is deferred.
  • OSV aggregation and OSV-converted NVD material are not independent corroboration.
  • Red Hat facts are vendor assertions for the exact supplied products.
  • Nonmembership and not-yet-observed states are not proof of safety.