Evidence dossier

CVE-2020-1380

Scripting Engine Memory Corruption Vulnerability

Exploited in the wild (CISA KEV since Nov 3, 2021). microsoft reports CVSS 3.1 7.8. Severity assessments differ within at least one CVSS version. EPSS estimates 24.2% exploit likelihood as of Aug 27, 2026.

72.076.0Priority evidence range
Evidence current through Aug 27, 2026, 6:09 PM UTC

As of Aug 27, 2026

Normalized restatement

A remote code execution vulnerability exists in the way that the scripting engine handles objects in memory in Internet Explorer. The vulnerability could corrupt memory in such a way that an attacker could execute arbitrary code in the context of the current user. An attacker who successfully exploited the vulnerability could gain the same user rights as the current user. If the current user is logged on with administrative user rights, an attacker who successfully exploited the vulnerability could take control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. In a web-based attack scenario, an attacker could host a specially crafted website that is designed to exploit the vulnerability through Internet Explorer and then convince a user to view the website. An attacker could also embed an ActiveX control marked "safe for initialization" in an application or Microsoft Office document that hosts the IE rendering engine. The attacker could also take advantage of compromised websites and websites that accept or host user-provided content or advertisements. These websites could contain specially crafted content that could exploit the vulnerability. The security update addresses the vulnerability by modifying how the scripting engine handles objects in memory.

State
PUBLISHED
Published
Aug 17, 2020
Updated
Oct 21, 2025
Evidence coverage
80%

Evidence chronology

What was known when

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  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: Scripting Engine Memory Corruption Vulnerability

    Inspect raw assertion
    Field
    container
    Value
    Scripting Engine Memory Corruption Vulnerability
    Original evidence ↗
  4. Source dateFirst observed by CASCA
    CISA KEV

    Exploitation cataloged: Microsoft Internet Explorer Scripting Engine Memory Corruption Vulnerability

    Inspect raw assertion
    Field
    observed_exploitation
    Value
    Microsoft Internet Explorer Scripting Engine Memory Corruption Vulnerability
    Original evidence ↗
  5. Source dateFirst observed by CASCA
    FIRST EPSS

    EPSS score: 24.19% probability · 97.68th percentile

    Inspect raw assertion
    Field
    model_probability
    Value
    Probability 0.241880000000; percentile 0.976820000000
    Original evidence ↗

Assessments differ

NVD7.6CVSS 2.0 · source date omitted
NVD8.8CVSS 3.1 · source date omitted
secure@microsoft.com7.8CVSS 3.1 · source date omitted

Values are shown separately by source and CVSS version.

ExploitationCatalog member

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

Exploit likelihood24.19%

FIRST EPSS · score date Aug 27, 2026 · 97.7th percentile · first observed Aug 27, 2026

SeverityAssessments differ

microsoft · CVSS 3.1 · first observed Jul 19, 2026 · values shown separately below

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 assessmentAssessments differ

Eligible assertions materially conflict and remain visible side by side.

Revision
casca-direct-cvss-eligibility-v1
Cutoff
Aug 27, 2026
Resolution
Resolve conflict
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

Scripting Engine Memory Corruption Vulnerability

Inspect raw assertion
Field
container
Value
Scripting Engine Memory Corruption Vulnerability
Source dateSource date omittedFirst observed by CASCAOriginal evidence ↗
CISA KEVOriginal assertion
Exploitation cataloged

Microsoft Internet Explorer Scripting Engine Memory Corruption Vulnerability

Inspect raw assertion
Field
observed_exploitation
Value
Microsoft Internet Explorer Scripting Engine Memory Corruption Vulnerability
Source dateFirst observed by CASCAOriginal evidence ↗
FIRST EPSSOriginal assertion
EPSS score

24.19% probability · 97.68th percentile

Inspect raw assertion
Field
model_probability
Value
Probability 0.241880000000; percentile 0.976820000000
Source dateFirst observed by CASCAOriginal evidence ↗

Applicability

Cited product scope

Trace impact →
17Underlying assertions
16Canonical products
1Target assertions
16Constraint assertions

Grouped from 2 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

17 scope groups

microsoft · source assertedMicrosoftInternet Explorer 11Direct source scope
Affected: 1.0.0 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": "1.0.0", "lessThan": "publication", "versionType": "custom"}]
NVD CPE · APPLICATIONmicrosoftinternet_explorerVulnerable target · 1 assertions
Version 11Canonical identity product-d26e3505f2452daa926474c7ca23fc78f73a7b20902783174428ff8d6e276baaLinked exact
Scope supported
Inspect raw assertion
  1. cpe:2.3:a:microsoft:internet_explorer:11:-:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 0
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    d7809f78-8d56-4925-a8f9-4119b973a667
NVD CPE · OPERATING SYSTEMmicrosoftwindows_10_1507Environmental constraint · 1 assertions
Version not applicableCanonical identity product-9851bd571b8ab08bca589cd73710badfef557d036f0fb7707f694f1c9f597cb4Linked exact
Scope constrained
Inspect raw assertion
  1. cpe:2.3:o:microsoft:windows_10_1507:-:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Environmental constraint
    Configuration
    0 · node/1 · match 0
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    542daeec-73cc-46c6-a630-bf474a3446ac
NVD CPE · OPERATING SYSTEMmicrosoftwindows_10_1607Environmental constraint · 1 assertions
Version not applicableCanonical identity product-740fec3e9838b5eabe76ebe27e4d0d7a4cb2e0ef7e13923300d3d0b51e3fce1cLinked exact
Scope constrained
Inspect raw assertion
  1. cpe:2.3:o:microsoft:windows_10_1607:-:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Environmental constraint
    Configuration
    0 · node/1 · match 1
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    61019899-d7af-46e4-a72c-d189180f66ab
NVD CPE · OPERATING SYSTEMmicrosoftwindows_10_1709Environmental constraint · 1 assertions
Version not applicableCanonical identity product-d059dbfcd39652adfca6d48669484008cb5d4a8b33116c81ee002cd9101904afLinked exact
Scope constrained
Inspect raw assertion
  1. cpe:2.3:o:microsoft:windows_10_1709:-:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Environmental constraint
    Configuration
    0 · node/1 · match 2
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    ac160b20-3ea0-49a0-a857-4e7a1c2d74e2
NVD CPE · OPERATING SYSTEMmicrosoftwindows_10_1803Environmental constraint · 1 assertions
Version not applicableCanonical identity product-5e821ea3746af154a469c180e78b9f4d663edf21461517987eed76740c7910c1Linked exact
Scope constrained
Inspect raw assertion
  1. cpe:2.3:o:microsoft:windows_10_1803:-:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Environmental constraint
    Configuration
    0 · node/1 · match 3
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    00345596-e9e0-4096-8dc6-0212f4747a13
NVD CPE · OPERATING SYSTEMmicrosoftwindows_10_1809Environmental constraint · 1 assertions
Version not applicableCanonical identity product-a3084138383423221f61594e86f5b295e5e254acd7ae5284f45e0877a084db43Linked exact
Scope constrained
Inspect raw assertion
  1. cpe:2.3:o:microsoft:windows_10_1809:-:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Environmental constraint
    Configuration
    0 · node/1 · match 4
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    2e332666-2e03-468e-bc30-299816d6e8ed
NVD CPE · OPERATING SYSTEMmicrosoftwindows_10_1903Environmental constraint · 1 assertions
Version not applicableCanonical identity product-9868fa1c12254f9aff51c0302ecb2ea1ab1d9ca0547bde09677154b24f8c7c61Linked exact
Scope constrained
Inspect raw assertion
  1. cpe:2.3:o:microsoft:windows_10_1903:-:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Environmental constraint
    Configuration
    0 · node/1 · match 5
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    a363ce8f-f399-4b6e-9e7d-349792f95ddb
NVD CPE · OPERATING SYSTEMmicrosoftwindows_10_1909Environmental constraint · 1 assertions
Version not applicableCanonical identity product-ef5324dcc791e4e872d6c2be0aefa1d7687ca82c3b4ac5d1f72c76cce8395218Linked exact
Scope constrained
Inspect raw assertion
  1. cpe:2.3:o:microsoft:windows_10_1909:-:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Environmental constraint
    Configuration
    0 · node/1 · match 6
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    a1b570a8-ed1a-46b6-b8ab-064445f8fc4c
NVD CPE · OPERATING SYSTEMmicrosoftwindows_10_2004Environmental constraint · 1 assertions
Version not applicableCanonical identity product-9b245936275be71b526838fc72ea633d195b35bdd9dfc31bb6df51e7700edeccLinked exact
Scope constrained
Inspect raw assertion
  1. cpe:2.3:o:microsoft:windows_10_2004:-:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Environmental constraint
    Configuration
    0 · node/1 · match 7
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    d4dbe5b2-ae10-4251-bcda-dc5edee6ee67
NVD CPE · OPERATING SYSTEMmicrosoftwindows_7Environmental constraint · 1 assertions
Version not applicableCanonical identity product-f20a05098a41a238f96b56b817d0482887bb39ad40620198bbe05da10ee02ffcLinked exact
Scope constrained
Inspect raw assertion
  1. cpe:2.3:o:microsoft:windows_7:-:sp1:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Environmental constraint
    Configuration
    0 · node/1 · match 8
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    c2b1c231-de19-4b8f-a4aa-5b3a65276e46
NVD CPE · OPERATING SYSTEMmicrosoftwindows_8.1Environmental constraint · 1 assertions
Version not applicableCanonical identity product-7e46de82012029583622f69d79b86bc210b5bd25b8cb3bb4468936702b23c4b0Linked exact
Scope constrained
Inspect raw assertion
  1. cpe:2.3:o:microsoft:windows_8.1:-:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Environmental constraint
    Configuration
    0 · node/1 · match 9
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    e93068db-549b-45ab-8e5c-00eb5d8b5cf8
NVD CPE · OPERATING SYSTEMmicrosoftwindows_rt_8.1Environmental constraint · 1 assertions
Version not applicableCanonical identity product-076c7e47c78d9425d54dea0b063ed7cd79e5f9f0bfdb3c9153b8aec4e71a7ad9Linked exact
Scope constrained
Inspect raw assertion
  1. cpe:2.3:o:microsoft:windows_rt_8.1:-:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Environmental constraint
    Configuration
    0 · node/1 · match 10
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    c6ce5198-c498-4672-af4c-77ab4be06c5c
NVD CPE · OPERATING SYSTEMmicrosoftwindows_server_2008Environmental constraint · 1 assertions
Version r2Canonical identity product-217b1ab3d25f361a639824f86753d418b35aa2a816ee370bb71b5d1dd883d87aLinked exact
Scope constrained
Inspect raw assertion
  1. cpe:2.3:o:microsoft:windows_server_2008:r2:sp1:*:*:*:*:x64:*
    Official link
    Linked exact
    Role
    Environmental constraint
    Configuration
    0 · node/1 · match 11
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    af07a81d-12e5-4b1d-bff9-c8d08c32ff4f
NVD CPE · OPERATING SYSTEMmicrosoftwindows_server_2012Environmental constraint · 2 assertions
Version not applicable; Version r2Canonical identity product-5a80416e92fed0cddbb3d4f3840218b448dee11159824ad25a0353da566963feLinked exact
Scope constrained
Inspect raw assertions
  1. cpe:2.3:o:microsoft:windows_server_2012:r2:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Environmental constraint
    Configuration
    0 · node/1 · match 13
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    db18c4ce-5917-401e-acf7-2747084fd36e
  2. cpe:2.3:o:microsoft:windows_server_2012:-:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Environmental constraint
    Configuration
    0 · node/1 · match 12
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    a7df96f8-ba6a-4780-9ca3-f719b3f81074
NVD CPE · OPERATING SYSTEMmicrosoftwindows_server_2016Environmental constraint · 1 assertions
Version not applicableCanonical identity product-02e254d111ce604757a15650ef469f4f8365d6247da82ce3ac2695c3cfc7dc5fLinked exact
Scope constrained
Inspect raw assertion
  1. cpe:2.3:o:microsoft:windows_server_2016:-:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Environmental constraint
    Configuration
    0 · node/1 · match 14
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    041ff8ba-0b12-4a1f-b4bf-9c4f33b7c1e7
NVD CPE · OPERATING SYSTEMmicrosoftwindows_server_2019Environmental constraint · 1 assertions
Version not applicableCanonical identity product-25a2932c0bbcb648f7e391c8b9d34c734e5085444c03c1c206b9d4c4baa80b25Linked exact
Scope constrained
Inspect raw assertion
  1. cpe:2.3:o:microsoft:windows_server_2019:-:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Environmental constraint
    Configuration
    0 · node/1 · match 15
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    db79ee26-fc32-417d-a49c-a1a63165a968

Affected-product evidence

Accepted scope and product mapping

1 canonical links · 1 source-reported links

Mapping establishedEvidence supported

vendor-01299a5a765aea70faa05f2d06e0c26a5d498fd34553e868d89e8a43b31864db · product-d26e3505f2452daa926474c7ca23fc78f73a7b20902783174428ff8d6e276baa

Source class
Nvd cpe vulnerable target
Assertions
1
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Aug 27, 2026
Retained assertion IDs
68fe01eb-9177-4a79-b23b-2c32b0955964
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
1
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Aug 27, 2026
Retained assertion IDs
98f00134-0797-4554-8706-fd6238cc7ad0

Assessments

CVSS by origin

7.6
NVDCVSS 2.0 · role Primary · priority eligiblevalid_matchAV:N/AC:H/Au:N/C:C/I:C/A:C
8.8
NVDCVSS 3.1 · role Secondary · priority eligiblevalid_matchCVSS:3.1/AV:N/AC:L/PR:N/UI:R/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:P/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:P/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.