CASCACascade Atlas

Evidence dossier

CVE-2024-21413

Microsoft Outlook Remote Code Execution Vulnerability

Exploited in the wild (CISA KEV since Feb 6, 2025). microsoft reports CVSS 3.1 9.8. EPSS estimates 94.7% exploit likelihood as of Oct 21, 2026.

84.0–93.1Priority evidence range
Evidence through Oct 22, 2026, 6:07 PM UTC

As of Oct 22, 2026

Normalized restatement

Microsoft Outlook Remote Code Execution Vulnerability

State
PUBLISHED
Published
Feb 13, 2024
Updated
Aug 10, 2026
Evidence coverage
85%

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: Microsoft Outlook Remote Code Execution Vulnerability

    Inspect raw assertion
    Field
    container
    Value
    Microsoft Outlook Remote Code Execution Vulnerability
    Original evidence ↗
  4. Source dateFirst observed by CASCA
    CISA KEV

    Exploitation cataloged: Microsoft Outlook Improper Input Validation Vulnerability

    Inspect raw assertion
    Field
    observed_exploitation
    Value
    Microsoft Outlook Improper Input Validation Vulnerability
    Original evidence ↗
  5. Source dateFirst observed by CASCA
    FIRST EPSS

    EPSS score: 94.66% probability · 99.86th percentile

    Inspect raw assertion
    Field
    model_probability
    Value
    Probability 0.946600000000; percentile 0.998590000000
    Original evidence ↗
ExploitationCatalog member

CISA KEV · catalog date Feb 6, 2025 · first observed Sep 1, 2026

Exploit likelihood94.66%

FIRST EPSS · score date Oct 21, 2026 · 99.9th percentile · first observed Oct 21, 2026

SeverityCVSS 9.8

microsoft · CVSS 3.1 · first observed Aug 10, 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 statusLast verified source snapshot retained

The last verified source boundary remains in force for this claim.

Revision
evidence-policy-v1.1.0
Cutoff
Oct 22, 2026
Resolution
Review source contract
Exploit likelihoodEvidence supported

Eligible evidence is present for this bounded claim.

Revision
evidence-policy-v1.1.0
Cutoff
Oct 22, 2026
Resolution
None
Severity assessmentEvidence supported

Eligible evidence is present for this bounded claim.

Revision
casca-direct-cvss-eligibility-v1
Cutoff
Oct 22, 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
Oct 22, 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

Microsoft Outlook Remote Code Execution Vulnerability

Inspect raw assertion
Field
container
Value
Microsoft Outlook Remote Code Execution Vulnerability
Source dateSource date omittedFirst observed by CASCAOriginal evidence ↗
CISA KEVOriginal assertion
Exploitation cataloged

Microsoft Outlook Improper Input Validation Vulnerability

Inspect raw assertion
Field
observed_exploitation
Value
Microsoft Outlook Improper Input Validation Vulnerability
Source dateFirst observed by CASCAOriginal evidence ↗
FIRST EPSSOriginal assertion
EPSS score

94.66% probability · 99.86th percentile

Inspect raw assertion
Field
model_probability
Value
Probability 0.946600000000; percentile 0.998590000000
Source dateFirst observed by CASCAOriginal evidence ↗

Applicability

Cited product scope

Trace impact →
6Underlying assertions
4Canonical products
6Target 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

8 scope groups

microsoft · source assertedMicrosoftMicrosoft 365 Apps for EnterpriseDirect source scope
Affected: 16.0.1 to before https://aka.ms/OfficeSecurityReleases (custom comparison)
Source-reported scope

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

Inspect raw assertion[{"status": "affected", "version": "16.0.1", "lessThan": "https://aka.ms/OfficeSecurityReleases", "versionType": "custom"}]
microsoft · source assertedMicrosoftMicrosoft Office 2016Direct source scope
Affected: 16.0.0 to before 16.0.5435.1001 (custom comparison)
Source-reported scope

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

Inspect raw assertion[{"status": "affected", "version": "16.0.0", "lessThan": "16.0.5435.1001", "versionType": "custom"}]
microsoft · source assertedMicrosoftMicrosoft Office 2019Direct source scope
Affected: 19.0.0 to before https://aka.ms/OfficeSecurityReleases (custom comparison)
Source-reported scope

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

Inspect raw assertion[{"status": "affected", "version": "19.0.0", "lessThan": "https://aka.ms/OfficeSecurityReleases", "versionType": "custom"}]
microsoft · source assertedMicrosoftMicrosoft Office LTSC 2021Direct source scope
Affected: 16.0.1 to before https://aka.ms/OfficeSecurityReleases (custom comparison)
Source-reported scope

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

Inspect raw assertion[{"status": "affected", "version": "16.0.1", "lessThan": "https://aka.ms/OfficeSecurityReleases", "versionType": "custom"}]
NVD CPE · APPLICATIONmicrosoft365_appsVulnerable target · 1 assertions
Version not applicableCanonical identity product-14a59f3c1c4fc4cec4da9e1d602ac339da114e67c884352e121c41fb03b7a712Linked exact
Scope supported
Inspect raw assertion
  1. cpe:2.3:a:microsoft:365_apps:-:*:*:*:enterprise:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 0
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    40c15edd-98d4-4d06-ba06-21ae0f33c72d
NVD CPE · APPLICATIONmicrosoftoffice_2016Vulnerable target · 2 assertions
Version not applicableCanonical identity product-f5c1cc30544816f250a4b79c059c21449afce8b3082dac67375bccd8f3cf0087Linked exact
Scope supported
Inspect raw assertions
  1. cpe:2.3:a:microsoft:office_2016:-:*:*:*:-:*:x86:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 2
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    bf3b9f15-3077-4bc5-9ec5-7416a9fbdc70
  2. cpe:2.3:a:microsoft:office_2016:-:*:*:*:-:*:x64:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 1
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    45a9ece7-f173-47ab-a420-0b6f64a04d21
NVD CPE · APPLICATIONmicrosoftoffice_2019Vulnerable target · 2 assertions
Version not applicableCanonical identity product-07fe6e8e7d1088248ce0f8f21edcbcad6b1c631bd4181f4000be16067f3175feLinked exact
Scope supported
Inspect raw assertions
  1. cpe:2.3:a:microsoft:office_2019:-:*:*:*:*:*:x86:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 4
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    14d63e3f-a431-4dd8-979f-811e8dac423d
  2. cpe:2.3:a:microsoft:office_2019:-:*:*:*:*:*:x64:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 3
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    241cde2b-abd0-4eff-8d73-1766e32fa20f
NVD CPE · APPLICATIONmicrosoftoffice_long_term_servicing_channelVulnerable target · 1 assertions
Version 2021Canonical identity product-911e466d0be7cb2953297756c47cb44a2f472c517f89b133f4ff5b03a0ab5264Linked exact
Scope supported
Inspect raw assertion
  1. cpe:2.3:a:microsoft:office_long_term_servicing_channel:2021:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 5
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    0b3ef1e5-4757-4cfa-ae72-6ba876d3c9fd

Affected-product evidence

Accepted scope and product mapping

0 canonical links · 2 source-reported links

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
4
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Oct 22, 2026
Retained assertion IDs
32bd2b6a-db79-4659-af78-63c17bbe190a3fd2b3ab-b77f-4fa7-a7e5-bbdcc50f198e88be3177-8a66-4222-8072-f8fe24117f12b6f56d65-64d2-4283-9e2e-067d0679f7a8
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
Nvd cpe vulnerable target
Assertions
6
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Oct 22, 2026
Retained assertion IDs
5047983b-6da2-4f9e-a883-ac1b3cebc7f163f9ed49-1d95-470c-8612-baa5ea47ffe9cc84ff19-092e-4e73-adb8-8e09d3c666b6d3414fa4-a6e1-48d6-8ae6-41e162b710fce21aba71-1910-46b6-86d1-02642e310883f8c6f5dc-f447-4e21-9f5c-8f8b5dc908fd

Assessments

CVSS by origin

9.8
secure@microsoft.comCVSS 3.1 · role Secondary · priority eligiblevalid_matchCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.8
microsoftCVSS 3.1 · role unknown · display onlyDirect record assessment retained outside normalized eligibilityCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C

Direct CVE/CNA normalized decisions

9.8Priority eligible

microsoft

CVSS 3.1 · Primary · Original assertion · rank 1

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
Validation
Valid match
Recomputed
9.8
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.