CASCACascade Atlas

Evidence dossier

CVE-2018-8589

An elevation of privilege vulnerability exists when Windows improperly handles calls to Win32k.sys, aka "Windows Win32k Elevation of Privilege Vulnerability." This affects…

Exploited in the wild (CISA KEV since May 23, 2022). NVD reports CVSS 3.1 7.8. EPSS estimates 3.0% exploit likelihood as of Aug 27, 2026.

66.5–69.5Priority evidence range
Evidence current through Aug 27, 2026, 6:09 PM UTC

As of Aug 27, 2026

Normalized restatement

An elevation of privilege vulnerability exists when Windows improperly handles calls to Win32k.sys, aka "Windows Win32k Elevation of Privilege Vulnerability." This affects Windows Server 2008, Windows 7, Windows Server 2008 R2.

State
PUBLISHED
Published
Nov 14, 2018
Updated
Oct 21, 2025
Evidence coverage
93%

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: An elevation of privilege vulnerability exists when Windows improperly handles calls to Win32k.sys, aka "Windows Win32k Elevation of Privilege Vulnerability." This affects Windows Server 2008, Windows 7, Windows Server 2008 R2.

    Inspect raw assertion
    Field
    container
    Value
    An elevation of privilege vulnerability exists when Windows improperly handles calls to Win32k.sys, aka "Windows Win32k Elevation of Privilege Vulnerability." This affects Windows Server 2008, Windows 7, Windows Server 2008 R2.
    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: 3.02% probability · 86.48th percentile

    Inspect raw assertion
    Field
    model_probability
    Value
    Probability 0.030230000000; percentile 0.864760000000
    Original evidence ↗
ExploitationCatalog member

CISA KEV · catalog date May 23, 2022 · first observed Jul 19, 2026

Exploit likelihood3.02%

FIRST EPSS · score date Aug 27, 2026 · 86.5th percentile · first observed Aug 27, 2026

SeverityCVSS 7.8

NVD · 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

An elevation of privilege vulnerability exists when Windows improperly handles calls to Win32k.sys, aka "Windows Win32k Elevation of Privilege Vulnerability." This affects Windows Server 2008, Windows 7, Windows Server 2008 R2.

Inspect raw assertion
Field
container
Value
An elevation of privilege vulnerability exists when Windows improperly handles calls to Win32k.sys, aka "Windows Win32k Elevation of Privilege Vulnerability." This affects Windows Server 2008, Windows 7, Windows Server 2008 R2.
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

3.02% probability · 86.48th percentile

Inspect raw assertion
Field
model_probability
Value
Probability 0.030230000000; percentile 0.864760000000
Source dateFirst observed by CASCAOriginal evidence ↗

Applicability

Cited product scope

Trace impact →
4Underlying assertions
2Canonical products
4Target 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

5 scope groups

microsoft · source assertedMicrosoftWindows 7Direct source scope
Affected: 32-bit Systems Service Pack 1Affected: x64-based Systems Service Pack 1
Source-reported scope

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

Inspect raw assertion[{"status": "affected", "version": "32-bit Systems Service Pack 1"}, {"status": "affected", "version": "x64-based Systems Service Pack 1"}]
microsoft · source assertedMicrosoftWindows Server 2008Direct source scope
Affected: 32-bit Systems Service Pack 2Affected: 32-bit Systems Service Pack 2 (Server Core installation)Affected: Itanium-Based Systems Service Pack 2Affected: x64-based Systems Service Pack 2Affected: x64-based Systems Service Pack 2 (Server Core installation)
Source-reported scope

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

Inspect raw assertion[{"status": "affected", "version": "32-bit Systems Service Pack 2"}, {"status": "affected", "version": "32-bit Systems Service Pack 2 (Server Core installation)"}, {"status": "affected", "version": "Itanium-Based Systems Service Pack 2"}, {"status": "affected", "version": "x64-based Systems Service Pack 2"}, {"status": "affected", "version": "x64-based Systems Service Pack 2 (Server Core installation)"}]
microsoft · source assertedMicrosoftWindows Server 2008 R2Direct source scope
Affected: Itanium-Based Systems Service Pack 1Affected: x64-based Systems Service Pack 1Affected: x64-based Systems Service Pack 1 (Server Core installation)
Source-reported scope

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

Inspect raw assertion[{"status": "affected", "version": "Itanium-Based Systems Service Pack 1"}, {"status": "affected", "version": "x64-based Systems Service Pack 1"}, {"status": "affected", "version": "x64-based Systems Service Pack 1 (Server Core installation)"}]
NVD CPE · OPERATING SYSTEMmicrosoftwindows_7Vulnerable target · 1 assertions
Version not applicableCanonical identity product-f20a05098a41a238f96b56b817d0482887bb39ad40620198bbe05da10ee02ffcLinked exact
Scope supported
Inspect raw assertion
  1. cpe:2.3:o:microsoft:windows_7:-:sp1:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 0
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    c2b1c231-de19-4b8f-a4aa-5b3a65276e46
NVD CPE · OPERATING SYSTEMmicrosoftwindows_server_2008Vulnerable target · 3 assertions
Version not applicable; Version r2Canonical identity product-217b1ab3d25f361a639824f86753d418b35aa2a816ee370bb71b5d1dd883d87aLinked exact
Scope supported
Inspect raw assertions
  1. cpe:2.3:o:microsoft:windows_server_2008:r2:sp1:*:*:*:*:itanium:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 2
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    b320a104-9037-487e-bc9a-62b4a6b49fd0
  2. cpe:2.3:o:microsoft:windows_server_2008:-:sp2:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 1
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    5f422a8c-2c4e-42c8-b420-e0728037e15c
  3. cpe:2.3:o:microsoft:windows_server_2008:r2:sp1:*:*:*:*:x64:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 3
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    af07a81d-12e5-4b1d-bff9-c8d08c32ff4f

Affected-product evidence

Accepted scope and product mapping

2 canonical links · 1 source-reported links

Mapping establishedEvidence supported

vendor-01299a5a765aea70faa05f2d06e0c26a5d498fd34553e868d89e8a43b31864db · product-217b1ab3d25f361a639824f86753d418b35aa2a816ee370bb71b5d1dd883d87a

Source class
Nvd cpe vulnerable target
Assertions
3
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Aug 27, 2026
Retained assertion IDs
5eb94e4e-9f47-4f43-b243-eaa9c52c4528b4d8fd21-4ae4-4b92-aba2-5c87ae340e4ce8ef0092-5ecf-49ed-8b5d-541ecb3ac328
Mapping establishedEvidence supported

vendor-01299a5a765aea70faa05f2d06e0c26a5d498fd34553e868d89e8a43b31864db · product-f20a05098a41a238f96b56b817d0482887bb39ad40620198bbe05da10ee02ffc

Source class
Nvd cpe vulnerable target
Assertions
1
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Aug 27, 2026
Retained assertion IDs
b4a38a93-b551-4ec6-8a15-38851ecf68dc
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
3
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Aug 27, 2026
Retained assertion IDs
09b6e69e-947e-40f4-b7d4-cbd0441e0d5719cf21a5-6870-4f48-b56e-c3a06c8bb7d668232e92-5411-43a5-97a1-4552ec6ec2e7

Assessments

CVSS by origin

7.8
NVDCVSS 3.1 · role Primary · priority eligiblevalid_matchCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.2
NVDCVSS 2.0 · role Primary · priority eligiblevalid_matchAV:L/AC:L/Au:N/C:C/I:C/A:C
7.8
CVE Program sourceCVSS 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
CISA-ADPCVSS 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

Direct CVE/CNA normalized decisions

7.8Priority eligible

CISA-ADP

CVSS 3.1 · Secondary · Independent enrichment · rank 2

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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.