CASCACascade Atlas

Evidence dossier

CVE-2025-21334

Windows Hyper-V NT Kernel Integration VSP Elevation of Privilege Vulnerability

Exploited in the wild (CISA KEV since Jan 14, 2025). microsoft reports CVSS 3.1 7.8. EPSS estimates 1.6% exploit likelihood as of Aug 27, 2026.

67.6–72.1Priority evidence range
Evidence current through Aug 27, 2026, 6:09 PM UTC

As of Aug 27, 2026

Normalized restatement

Windows Hyper-V NT Kernel Integration VSP Elevation of Privilege Vulnerability

State
PUBLISHED
Published
Jan 14, 2025
Updated
Jun 9, 2026
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
    microsoft

    Record text: Windows Hyper-V NT Kernel Integration VSP Elevation of Privilege Vulnerability

    Inspect raw assertion
    Field
    container
    Value
    Windows Hyper-V NT Kernel Integration VSP Elevation of Privilege Vulnerability
    Original evidence ↗
  3. Source dateFirst observed by CASCA
    CISA KEV

    Exploitation cataloged: Microsoft Windows Hyper-V NT Kernel Integration VSP Use-After-Free Vulnerability

    Inspect raw assertion
    Field
    observed_exploitation
    Value
    Microsoft Windows Hyper-V NT Kernel Integration VSP Use-After-Free Vulnerability
    Original evidence ↗
  4. Source dateFirst observed by CASCA
    FIRST EPSS

    EPSS score: 1.56% probability · 73.42th percentile

    Inspect raw assertion
    Field
    model_probability
    Value
    Probability 0.015610000000; percentile 0.734190000000
    Original evidence ↗
ExploitationCatalog member

CISA KEV · catalog date Jan 14, 2025 · first observed Jul 19, 2026

Exploit likelihood1.56%

FIRST EPSS · score date Aug 27, 2026 · 73.4th 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 ↗
microsoftOriginal assertion
Record text

Windows Hyper-V NT Kernel Integration VSP Elevation of Privilege Vulnerability

Inspect raw assertion
Field
container
Value
Windows Hyper-V NT Kernel Integration VSP Elevation of Privilege Vulnerability
Source dateSource date omittedFirst observed by CASCAOriginal evidence ↗
CISA KEVOriginal assertion
Exploitation cataloged

Microsoft Windows Hyper-V NT Kernel Integration VSP Use-After-Free Vulnerability

Inspect raw assertion
Field
observed_exploitation
Value
Microsoft Windows Hyper-V NT Kernel Integration VSP Use-After-Free Vulnerability
Source dateFirst observed by CASCAOriginal evidence ↗
FIRST EPSSOriginal assertion
EPSS score

1.56% probability · 73.42th percentile

Inspect raw assertion
Field
model_probability
Value
Probability 0.015610000000; percentile 0.734190000000
Source dateFirst observed by CASCAOriginal evidence ↗

Applicability

Cited product scope

Trace impact →
10Underlying assertions
7Canonical products
10Target 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

16 scope groups

microsoft · source assertedMicrosoftWindows 10 Version 21H2Direct source scope
Affected: 10.0.19044.0 to before 10.0.19044.5371 (custom comparison)
Source-reported scope

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

Inspect raw assertion[{"status": "affected", "version": "10.0.19044.0", "lessThan": "10.0.19044.5371", "versionType": "custom"}]
microsoft · source assertedMicrosoftWindows 10 Version 22H2Direct source scope
Affected: 10.0.19045.0 to before 10.0.19045.5371 (custom comparison)
Source-reported scope

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

Inspect raw assertion[{"status": "affected", "version": "10.0.19045.0", "lessThan": "10.0.19045.5371", "versionType": "custom"}]
microsoft · source assertedMicrosoftWindows 11 version 22H2Direct source scope
Affected: 10.0.22621.0 to before 10.0.22621.4751 (custom comparison)
Source-reported scope

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

Inspect raw assertion[{"status": "affected", "version": "10.0.22621.0", "lessThan": "10.0.22621.4751", "versionType": "custom"}]
microsoft · source assertedMicrosoftWindows 11 version 22H3Direct source scope
Affected: 10.0.22631.0 to before 10.0.22631.4751 (custom comparison)
Source-reported scope

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

Inspect raw assertion[{"status": "affected", "version": "10.0.22631.0", "lessThan": "10.0.22631.4751", "versionType": "custom"}]
microsoft · source assertedMicrosoftWindows 11 Version 23H2Direct source scope
Affected: 10.0.22631.0 to before 10.0.22631.4751 (custom comparison)
Source-reported scope

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

Inspect raw assertion[{"status": "affected", "version": "10.0.22631.0", "lessThan": "10.0.22631.4751", "versionType": "custom"}]
microsoft · source assertedMicrosoftWindows 11 Version 24H2Direct source scope
Affected: 10.0.26100.0 to before 10.0.26100.2894 (custom comparison)
Source-reported scope

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

Inspect raw assertion[{"status": "affected", "version": "10.0.26100.0", "lessThan": "10.0.26100.2894", "versionType": "custom"}]
microsoft · source assertedMicrosoftWindows Server 2022, 23H2 Edition (Server Core installation)Direct source scope
Affected: 10.0.25398.0 to before 10.0.25398.1369 (custom comparison)
Source-reported scope

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

Inspect raw assertion[{"status": "affected", "version": "10.0.25398.0", "lessThan": "10.0.25398.1369", "versionType": "custom"}]
microsoft · source assertedMicrosoftWindows Server 2025Direct source scope
Affected: 10.0.26100.0 to before 10.0.26100.2894 (custom comparison)
Source-reported scope

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

Inspect raw assertion[{"status": "affected", "version": "10.0.26100.0", "lessThan": "10.0.26100.2894", "versionType": "custom"}]
microsoft · source assertedMicrosoftWindows Server 2025 (Server Core installation)Direct source scope
Affected: 10.0.26100.0 to before 10.0.26100.2894 (custom comparison)
Source-reported scope

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

Inspect raw assertion[{"status": "affected", "version": "10.0.26100.0", "lessThan": "10.0.26100.2894", "versionType": "custom"}]
NVD CPE · OPERATING SYSTEMmicrosoftwindows_10_21h2Vulnerable target · 1 assertions
Any version (unconstrained) (< 10.0.19044.5371)Canonical identity product-ec10c9f400f23fdf118887f60fe116ffde4adb76dcf118cdd3a7556fd033da3bLinked exact
Scope supported
Inspect raw assertion
  1. cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:x64:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 0
    Logic
    OR
    Version bounds
    through excluding 10.0.19044.5371
    Match ID
    c4af6108-e473-4695-b5ae-a4449a7a6e22
NVD CPE · OPERATING SYSTEMmicrosoftwindows_10_22h2Vulnerable target · 1 assertions
Any version (unconstrained) (< 10.0.19045.5371)Canonical identity product-a6295b9daad3ca57ce70751badba5b7fe99229c8a562cc7400e8cfef3daccaeeLinked exact
Scope supported
Inspect raw assertion
  1. cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:x64:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 1
    Logic
    OR
    Version bounds
    through excluding 10.0.19045.5371
    Match ID
    146c68db-cb79-4cca-bccf-ddb7e6b543dc
NVD CPE · OPERATING SYSTEMmicrosoftwindows_11_22h2Vulnerable target · 2 assertions
Any version (unconstrained) (< 10.0.22621.4751)Canonical identity product-f8c509b6ec25f2a4338a23556be321da5a7c3e8da9f1a4c52f7f15dd0e9a0d2aLinked exact
Scope supported
Inspect raw assertions
  1. cpe:2.3:o:microsoft:windows_11_22h2:*:*:*:*:*:*:x64:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 3
    Logic
    OR
    Version bounds
    through excluding 10.0.22621.4751
    Match ID
    8092b56b-2b8d-43f0-8509-98788a8c26d8
  2. cpe:2.3:o:microsoft:windows_11_22h2:*:*:*:*:*:*:arm64:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 2
    Logic
    OR
    Version bounds
    through excluding 10.0.22621.4751
    Match ID
    a9ddb80c-ca0e-4bf2-ab22-5240dfd39d1b
NVD CPE · OPERATING SYSTEMmicrosoftwindows_11_23h2Vulnerable target · 2 assertions
Any version (unconstrained) (< 10.0.22631.4751)Canonical identity product-026201767813843a6d53867bacde4a55c3035cb868c0a72434012c5e30dab148Linked exact
Scope supported
Inspect raw assertions
  1. cpe:2.3:o:microsoft:windows_11_23h2:*:*:*:*:*:*:x64:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 5
    Logic
    OR
    Version bounds
    through excluding 10.0.22631.4751
    Match ID
    bb980ebb-388d-4d0b-8154-c15ec4e77757
  2. cpe:2.3:o:microsoft:windows_11_23h2:*:*:*:*:*:*:arm64:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 4
    Logic
    OR
    Version bounds
    through excluding 10.0.22631.4751
    Match ID
    2c70bb15-a938-4882-89fa-a865f308aa3b
NVD CPE · OPERATING SYSTEMmicrosoftwindows_11_24h2Vulnerable target · 2 assertions
Any version (unconstrained) (< 10.0.26100.2894)Canonical identity product-8665879a2f5fe8b8eab868c43d6ace340b95d1f3879639d97ebdf60ef7b49b5fLinked exact
Scope supported
Inspect raw assertions
  1. cpe:2.3:o:microsoft:windows_11_24h2:*:*:*:*:*:*:arm64:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 6
    Logic
    OR
    Version bounds
    through excluding 10.0.26100.2894
    Match ID
    a491d1f2-50ef-4b26-8fa0-70484bd32e7a
  2. cpe:2.3:o:microsoft:windows_11_24h2:*:*:*:*:*:*:x64:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 7
    Logic
    OR
    Version bounds
    through excluding 10.0.26100.2894
    Match ID
    f187e54e-e615-444b-96c2-47222438b893
NVD CPE · OPERATING SYSTEMmicrosoftwindows_server_2022_23h2Vulnerable target · 1 assertions
Any version (unconstrained) (< 10.0.25398.1369)Canonical identity product-bc66b50eed682b3633d0f3a2914725d0a72d6d0d5fece14f566d91bc87448c0bLinked exact
Scope supported
Inspect raw assertion
  1. cpe:2.3:o:microsoft:windows_server_2022_23h2:*:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 8
    Logic
    OR
    Version bounds
    through excluding 10.0.25398.1369
    Match ID
    e3e0c061-2da7-4237-9607-f6792dc92dd3
NVD CPE · OPERATING SYSTEMmicrosoftwindows_server_2025Vulnerable target · 1 assertions
Any version (unconstrained) (< 10.0.26100.2894)Canonical identity product-3fe7da0d567cbba9da3f09deea827ccacd90ac3643fc3e1622f75fb001f24443Linked exact
Scope supported
Inspect raw assertion
  1. cpe:2.3:o:microsoft:windows_server_2025:*:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 9
    Logic
    OR
    Version bounds
    through excluding 10.0.26100.2894
    Match ID
    155593be-9192-4286-81f7-2c66b55b0438

Affected-product evidence

Accepted scope and product mapping

7 canonical links · 1 source-reported links

Mapping establishedEvidence supported

vendor-01299a5a765aea70faa05f2d06e0c26a5d498fd34553e868d89e8a43b31864db · product-026201767813843a6d53867bacde4a55c3035cb868c0a72434012c5e30dab148

Source class
Nvd cpe vulnerable target
Assertions
2
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Aug 27, 2026
Retained assertion IDs
4f53b70b-b2c3-4ac8-91e9-d63509c97a1654f8f158-ad2c-4dd4-ae80-29e839821e70
Mapping establishedEvidence supported

vendor-01299a5a765aea70faa05f2d06e0c26a5d498fd34553e868d89e8a43b31864db · product-3fe7da0d567cbba9da3f09deea827ccacd90ac3643fc3e1622f75fb001f24443

Source class
Nvd cpe vulnerable target
Assertions
1
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Aug 27, 2026
Retained assertion IDs
f23dad19-5ff9-4cc3-bbb2-1d263cc4d3a4
Mapping establishedEvidence supported

vendor-01299a5a765aea70faa05f2d06e0c26a5d498fd34553e868d89e8a43b31864db · product-8665879a2f5fe8b8eab868c43d6ace340b95d1f3879639d97ebdf60ef7b49b5f

Source class
Nvd cpe vulnerable target
Assertions
2
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Aug 27, 2026
Retained assertion IDs
cb61b568-12ba-48a4-9fd9-bd90fcbfd132f56e422f-ff78-4e3c-81f4-9514fb1b9b28
Mapping establishedEvidence supported

vendor-01299a5a765aea70faa05f2d06e0c26a5d498fd34553e868d89e8a43b31864db · product-a6295b9daad3ca57ce70751badba5b7fe99229c8a562cc7400e8cfef3daccaee

Source class
Nvd cpe vulnerable target
Assertions
1
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Aug 27, 2026
Retained assertion IDs
4f42a9e6-2241-4f2b-8802-ae0f103c3325
Mapping establishedEvidence supported

vendor-01299a5a765aea70faa05f2d06e0c26a5d498fd34553e868d89e8a43b31864db · product-bc66b50eed682b3633d0f3a2914725d0a72d6d0d5fece14f566d91bc87448c0b

Source class
Nvd cpe vulnerable target
Assertions
1
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Aug 27, 2026
Retained assertion IDs
933be61e-a660-48ac-acbf-595a84b3531b
Mapping establishedEvidence supported

vendor-01299a5a765aea70faa05f2d06e0c26a5d498fd34553e868d89e8a43b31864db · product-ec10c9f400f23fdf118887f60fe116ffde4adb76dcf118cdd3a7556fd033da3b

Source class
Nvd cpe vulnerable target
Assertions
1
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Aug 27, 2026
Retained assertion IDs
a16b81ac-8b8c-4499-a35f-69df3714d727
Mapping establishedEvidence supported

vendor-01299a5a765aea70faa05f2d06e0c26a5d498fd34553e868d89e8a43b31864db · product-f8c509b6ec25f2a4338a23556be321da5a7c3e8da9f1a4c52f7f15dd0e9a0d2a

Source class
Nvd cpe vulnerable target
Assertions
2
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Aug 27, 2026
Retained assertion IDs
56529467-2363-4643-98bc-53938b8b02f459915aec-4a8c-4be3-816a-9aeba720d3c4
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
9
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Aug 27, 2026
Retained assertion IDs
13731959-6408-4ec9-b485-339d7ed95a7d1c96bb64-eff2-48e8-ad0e-b0e8562840ad5b92df1f-4067-4062-bcbb-462487fd3a9a87dc3c14-e60f-42ec-8748-eb5684d89c928f07355b-ff18-45ff-90ff-679ab1388d69a3e74faa-040b-467d-b9c3-86c00676dcdcad1e54af-d8b2-4d64-89f4-57406d80b028c0ec5a90-2071-4888-b49d-700b171de596ec1e8cb0-2d7f-4f59-a814-ef1e61979379

Assessments

CVSS by origin

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:U/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:U/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.