CISA KEV · catalog date Nov 3, 2021 · first observed Jul 19, 2026
Evidence dossier
CVE-2021-33771
Windows Kernel Elevation of Privilege Vulnerability
Exploited in the wild (CISA KEV since Nov 3, 2021). microsoft reports CVSS 3.1 7.8. EPSS estimates 10.2% exploit likelihood as of Aug 27, 2026.
As of Aug 27, 2026
Normalized restatement
Windows Kernel Elevation of Privilege Vulnerability
- State
- PUBLISHED
- Published
- Jul 14, 2021
- Updated
- Oct 21, 2025
- Evidence coverage
- 92%
Evidence chronology
What was known when
- Source dateSource date omittedFirst observed by CASCACISA-ADPOriginal evidence ↗
Record text: CISA ADP Vulnrichment
Inspect raw assertion
- Field
container- Value
- CISA ADP Vulnrichment
- Source dateSource date omittedFirst observed by CASCACVE ProgramOriginal evidence ↗
Record text: CVE Program Container
Inspect raw assertion
- Field
container- Value
- CVE Program Container
- Source dateSource date omittedFirst observed by CASCAmicrosoftOriginal evidence ↗
Record text: Windows Kernel Elevation of Privilege Vulnerability
Inspect raw assertion
- Field
container- Value
- Windows Kernel Elevation of Privilege Vulnerability
- Source dateFirst observed by CASCACISA KEVOriginal evidence ↗
Exploitation cataloged: Microsoft Windows Kernel Privilege Escalation Vulnerability
Inspect raw assertion
- Field
observed_exploitation- Value
- Microsoft Windows Kernel Privilege Escalation Vulnerability
- Source dateFirst observed by CASCAFIRST EPSSOriginal evidence ↗
EPSS score: 10.17% probability · 95.31th percentile
Inspect raw assertion
- Field
model_probability- Value
- Probability 0.101720000000; percentile 0.953090000000
FIRST EPSS · score date Aug 27, 2026 · 95.3th percentile · first observed Aug 27, 2026
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-v1Eligible evidence is present for this bounded claim.
- Revision
- evidence-policy-v1.1.0
- Cutoff
- Aug 27, 2026
- Resolution
- None
Eligible evidence is present for this bounded claim.
- Revision
- evidence-policy-v1.1.0
- Cutoff
- Aug 27, 2026
- Resolution
- None
Eligible evidence is present for this bounded claim.
- Revision
- casca-direct-cvss-eligibility-v1
- Cutoff
- Aug 27, 2026
- Resolution
- None
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 ADP Vulnrichment
Inspect raw assertion
- Field
container- Value
- CISA ADP Vulnrichment
CVE Program Container
Inspect raw assertion
- Field
container- Value
- CVE Program Container
Windows Kernel Elevation of Privilege Vulnerability
Inspect raw assertion
- Field
container- Value
- Windows Kernel Elevation of Privilege Vulnerability
Microsoft Windows Kernel Privilege Escalation Vulnerability
Inspect raw assertion
- Field
observed_exploitation- Value
- Microsoft Windows Kernel Privilege Escalation Vulnerability
10.17% probability · 95.31th percentile
Inspect raw assertion
- Field
model_probability- Value
- Probability 0.101720000000; percentile 0.953090000000
Applicability
Cited product scope
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 2026-07-21T06:45:29.809Z
27d65b0f-b718-4b4f-bb79-c47c68d09dfa - Cpe match643,502 records · observed through 2026-07-21T08:13:17.697Z
955dae73-7302-438b-aee1-058d7cc5d48e
31 scope groups
Canonical linkage remains open; the cited source assertion is retained below.
Inspect raw assertion
[{"status": "affected", "version": "10.0.0", "lessThan": "10.0.10240.19003", "versionType": "custom"}]Canonical linkage remains open; the cited source assertion is retained below.
Inspect raw assertion
[{"status": "affected", "version": "10.0.0", "lessThan": "10.0.14393.4530", "versionType": "custom"}]Canonical linkage remains open; the cited source assertion is retained below.
Inspect raw assertion
[{"status": "affected", "version": "10.0.0", "lessThan": "10.0.17763.2061", "versionType": "custom"}]Canonical linkage remains open; the cited source assertion is retained below.
Inspect raw assertion
[{"status": "affected", "version": "10.0.0", "lessThan": "10.0.18363.1679", "versionType": "custom"}]Canonical linkage remains open; the cited source assertion is retained below.
Inspect raw assertion
[{"status": "affected", "version": "10.0.0", "lessThan": "10.0.19041.1110", "versionType": "custom"}]Canonical linkage remains open; the cited source assertion is retained below.
Inspect raw assertion
[{"status": "affected", "version": "10.0.0", "lessThan": "10.0.19042.1110", "versionType": "custom"}]Canonical linkage remains open; the cited source assertion is retained below.
Inspect raw assertion
[{"status": "affected", "version": "10.0.0", "lessThan": "10.0.19043.1110", "versionType": "custom"}]Canonical linkage remains open; the cited source assertion is retained below.
Inspect raw assertion
[{"status": "affected", "version": "6.3.0", "lessThan": "6.3.9600.20069", "versionType": "custom"}]Canonical linkage remains open; the cited source assertion is retained below.
Inspect raw assertion
[{"status": "affected", "version": "6.3.0", "lessThan": "6.3.9600.20069", "versionType": "custom"}]Canonical linkage remains open; the cited source assertion is retained below.
Inspect raw assertion
[{"status": "affected", "version": "6.3.0", "lessThan": "6.3.9600.20069", "versionType": "custom"}]Canonical linkage remains open; the cited source assertion is retained below.
Inspect raw assertion
[{"status": "affected", "version": "10.0.0", "lessThan": "10.0.14393.4530", "versionType": "custom"}]Canonical linkage remains open; the cited source assertion is retained below.
Inspect raw assertion
[{"status": "affected", "version": "10.0.0", "lessThan": "10.0.14393.4530", "versionType": "custom"}]Canonical linkage remains open; the cited source assertion is retained below.
Inspect raw assertion
[{"status": "affected", "version": "10.0.0", "lessThan": "10.0.17763.2061", "versionType": "custom"}]Canonical linkage remains open; the cited source assertion is retained below.
Inspect raw assertion
[{"status": "affected", "version": "10.0.0", "lessThan": "10.0.17763.2061", "versionType": "custom"}]Canonical linkage remains open; the cited source assertion is retained below.
Inspect raw assertion
[{"status": "affected", "version": "10.0.0", "lessThan": "10.0.19041.1110", "versionType": "custom"}]Canonical linkage remains open; the cited source assertion is retained below.
Inspect raw assertion
[{"status": "affected", "version": "10.0.0", "lessThan": "10.0.19042.1110", "versionType": "custom"}]product-9851bd571b8ab08bca589cd73710badfef557d036f0fb7707f694f1c9f597cb4Linked exactInspect raw assertion
cpe:2.3:o:microsoft:windows_10_1507:*:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Vulnerable target
- Configuration
- 0 · node/0 · match 0
- Logic
- OR
- Version bounds
- through excluding 10.0.10240.19003
- Match ID
0c51cd3a-e78b-4a0d-8716-4f2c0a79ed68
product-740fec3e9838b5eabe76ebe27e4d0d7a4cb2e0ef7e13923300d3d0b51e3fce1cLinked exactInspect raw assertion
cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Vulnerable target
- Configuration
- 0 · node/0 · match 1
- Logic
- OR
- Version bounds
- through excluding 10.0.14393.4530
- Match ID
9eebf8ac-ab6e-4f62-811a-0e53721c78f5
product-a3084138383423221f61594e86f5b295e5e254acd7ae5284f45e0877a084db43Linked exactInspect raw assertion
cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Vulnerable target
- Configuration
- 0 · node/0 · match 2
- Logic
- OR
- Version bounds
- through excluding 10.0.17763.2061
- Match ID
5baabe12-c0e8-4e34-9efe-18dd50c54b1d
product-ef5324dcc791e4e872d6c2be0aefa1d7687ca82c3b4ac5d1f72c76cce8395218Linked exactInspect raw assertion
cpe:2.3:o:microsoft:windows_10_1909:*:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Vulnerable target
- Configuration
- 0 · node/0 · match 3
- Logic
- OR
- Version bounds
- through excluding 10.0.18363.1679
- Match ID
1c9e359b-5719-48b1-babb-618744c73388
product-9b245936275be71b526838fc72ea633d195b35bdd9dfc31bb6df51e7700edeccLinked exactInspect raw assertion
cpe:2.3:o:microsoft:windows_10_2004:*:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Vulnerable target
- Configuration
- 0 · node/0 · match 4
- Logic
- OR
- Version bounds
- through excluding 10.0.19041.1110
- Match ID
307c13cf-563b-46d1-9f2e-227ab9c40720
product-55e90faed8848f3d316cf702d119e83086b6dc5a963d9947a7df1c589f50346dLinked exactInspect raw assertion
cpe:2.3:o:microsoft:windows_10_20h2:*:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Vulnerable target
- Configuration
- 0 · node/0 · match 5
- Logic
- OR
- Version bounds
- through excluding 10.0.19042.1110
- Match ID
9aec53c7-c1cb-4ffb-8069-27604fb50f0b
product-e0c6c3f5c5e95b5b83fbbf719a7de2471749e1ca250bebf19bc7898a937a00edLinked exactInspect raw assertion
cpe:2.3:o:microsoft:windows_10_21h1:*:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Vulnerable target
- Configuration
- 0 · node/0 · match 6
- Logic
- OR
- Version bounds
- through excluding 10.0.19043.1110
- Match ID
765ba052-1b41-4cd3-98e6-f3750e0466e5
product-7e46de82012029583622f69d79b86bc210b5bd25b8cb3bb4468936702b23c4b0Linked exactInspect raw assertion
cpe:2.3:o:microsoft:windows_8.1:-:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Vulnerable target
- Configuration
- 0 · node/0 · match 7
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
e93068db-549b-45ab-8e5c-00eb5d8b5cf8
product-076c7e47c78d9425d54dea0b063ed7cd79e5f9f0bfdb3c9153b8aec4e71a7ad9Linked exactInspect raw assertion
cpe:2.3:o:microsoft:windows_rt_8.1:-:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Vulnerable target
- Configuration
- 0 · node/0 · match 8
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
c6ce5198-c498-4672-af4c-77ab4be06c5c
Affected-product evidence
Accepted scope and product mapping
15 canonical links · 1 source-reported links
vendor-01299a5a765aea70faa05f2d06e0c26a5d498fd34553e868d89e8a43b31864db · product-02e254d111ce604757a15650ef469f4f8365d6247da82ce3ac2695c3cfc7dc5f
- Source class
- Nvd cpe vulnerable target
- Assertions
- 1
- Mapping revision
- cpe23-exact-mapping-v1
- Observed cutoff
- Aug 27, 2026
Retained assertion IDs
48130cfb-15d1-4e06-8929-8dba3fcd2fdbvendor-01299a5a765aea70faa05f2d06e0c26a5d498fd34553e868d89e8a43b31864db · product-076c7e47c78d9425d54dea0b063ed7cd79e5f9f0bfdb3c9153b8aec4e71a7ad9
- Source class
- Nvd cpe vulnerable target
- Assertions
- 1
- Mapping revision
- cpe23-exact-mapping-v1
- Observed cutoff
- Aug 27, 2026
Retained assertion IDs
142b55f3-f918-49b1-9593-3a4c503685cavendor-01299a5a765aea70faa05f2d06e0c26a5d498fd34553e868d89e8a43b31864db · product-217b1ab3d25f361a639824f86753d418b35aa2a816ee370bb71b5d1dd883d87a
- Source class
- Nvd cpe vulnerable target
- Assertions
- 2
- Mapping revision
- cpe23-exact-mapping-v1
- Observed cutoff
- Aug 27, 2026
Retained assertion IDs
366015e1-7870-44a4-b4ec-4311a1b5e764ad40e54f-c7eb-4cfe-a7cc-44c0a7c2a703vendor-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
c319a54c-0df4-4c11-8d43-abaf2cb7f521vendor-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
63aac3e3-9e9a-4667-b01d-d17794bf23f3vendor-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
5560f7db-75ee-4c56-a981-f2d0b7d1e8c0vendor-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
78e665f2-4385-4712-9a43-5e90811fa7e3vendor-01299a5a765aea70faa05f2d06e0c26a5d498fd34553e868d89e8a43b31864db · product-5a80416e92fed0cddbb3d4f3840218b448dee11159824ad25a0353da566963fe
- Source class
- Nvd cpe vulnerable target
- Assertions
- 1
- Mapping revision
- cpe23-exact-mapping-v1
- Observed cutoff
- Aug 27, 2026
Retained assertion IDs
aa49794d-2c98-4af8-8d5a-f716ba702a27vendor-01299a5a765aea70faa05f2d06e0c26a5d498fd34553e868d89e8a43b31864db · product-740fec3e9838b5eabe76ebe27e4d0d7a4cb2e0ef7e13923300d3d0b51e3fce1c
- Source class
- Nvd cpe vulnerable target
- Assertions
- 1
- Mapping revision
- cpe23-exact-mapping-v1
- Observed cutoff
- Aug 27, 2026
Retained assertion IDs
f7d3158a-6fe1-4676-b55e-573eb1be066bvendor-01299a5a765aea70faa05f2d06e0c26a5d498fd34553e868d89e8a43b31864db · product-7e46de82012029583622f69d79b86bc210b5bd25b8cb3bb4468936702b23c4b0
- Source class
- Nvd cpe vulnerable target
- Assertions
- 1
- Mapping revision
- cpe23-exact-mapping-v1
- Observed cutoff
- Aug 27, 2026
Retained assertion IDs
8afd6486-47c6-4ec6-bf94-b7d52c162637vendor-01299a5a765aea70faa05f2d06e0c26a5d498fd34553e868d89e8a43b31864db · product-9851bd571b8ab08bca589cd73710badfef557d036f0fb7707f694f1c9f597cb4
- Source class
- Nvd cpe vulnerable target
- Assertions
- 1
- Mapping revision
- cpe23-exact-mapping-v1
- Observed cutoff
- Aug 27, 2026
Retained assertion IDs
6b11f50e-a79d-42fe-bf62-babced7d4a43vendor-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
728daaf8-aaa0-4a4d-aba7-060acf646620vendor-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
6b678127-4d36-455b-9949-7fc3b895a672vendor-01299a5a765aea70faa05f2d06e0c26a5d498fd34553e868d89e8a43b31864db · product-e0c6c3f5c5e95b5b83fbbf719a7de2471749e1ca250bebf19bc7898a937a00ed
- Source class
- Nvd cpe vulnerable target
- Assertions
- 1
- Mapping revision
- cpe23-exact-mapping-v1
- Observed cutoff
- Aug 27, 2026
Retained assertion IDs
52c9d01c-d416-4b99-940e-29c493b770f6vendor-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
cfd9b1ed-ba54-4533-b3da-9a387a359adcCanonical 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
- 16
- Mapping revision
- cpe23-exact-mapping-v1
- Observed cutoff
- Aug 27, 2026
Retained assertion IDs
552c6595-3860-4f76-91be-b443ecc564485e0199dc-7e88-47fb-9708-98f639f2928b683fd15c-e52a-4590-8188-4256d38bdb8d6e465293-da87-491a-b451-4b87f1bbf25e75443871-5c59-4766-bc03-ef1bb022467a8f0f6287-d8b0-419a-9586-c38ef4bad0339609e230-4650-4692-872f-4723932669d7b1c0bc6c-0ed6-4db6-9319-2a46c6fede6ab5071194-1b44-4315-9506-5147cfd230f0c48bf9fd-26a2-4bd2-b93f-43dd8f5673a0c59434e9-f8b9-46b9-9f9d-8719dd417346d6a31d40-3eed-4073-9b5c-0990aabe6c56dc50c911-f7f4-4389-ac54-d3e755076e30e0c0f662-d915-4f96-a50c-89672046605ef27a2f86-180b-4e38-b907-c0f6ca44bd33fa978c71-23e2-4b0f-b787-47477969bb4dAssessments
CVSS by origin
AV:L/AC:L/Au:N/C:C/I:C/A:CCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:CDirect CVE/CNA normalized decisions
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.