CASCACascade Atlas

Evidence dossier

CVE-2020-5741

Deserialization of Untrusted Data in Plex Media Server on Windows allows a remote, authenticated attacker to execute arbitrary Python code.

Exploited in the wild (CISA KEV since Mar 10, 2023). NVD reports CVSS 3.1 7.2. EPSS estimates 72.9% exploit likelihood as of Aug 26, 2026.

77.7–79.3Priority evidence range
Evidence current through Aug 27, 2026, 6:09 PM UTC

As of Aug 27, 2026

Normalized restatement

Deserialization of Untrusted Data in Plex Media Server on Windows allows a remote, authenticated attacker to execute arbitrary Python code.

State
PUBLISHED
Published
May 8, 2020
Updated
Oct 21, 2025
Evidence coverage
92%

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

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    Field
    container
    Value
    CISA ADP Vulnrichment
    Original evidence ↗
  2. Source dateSource date omittedFirst observed by CASCA
    CVE Program

    Record text: CVE Program Container

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    Field
    container
    Value
    CVE Program Container
    Original evidence ↗
  3. Source dateSource date omittedFirst observed by CASCA
    tenable

    Record text: Deserialization of Untrusted Data in Plex Media Server on Windows allows a remote, authenticated attacker to execute arbitrary Python code.

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    Field
    container
    Value
    Deserialization of Untrusted Data in Plex Media Server on Windows allows a remote, authenticated attacker to execute arbitrary Python code.
    Original evidence ↗
  4. Source dateFirst observed by CASCA
    CISA KEV

    Exploitation cataloged: Plex Media Server Remote Code Execution Vulnerability

    Inspect raw assertion
    Field
    observed_exploitation
    Value
    Plex Media Server Remote Code Execution Vulnerability
    Original evidence ↗
  5. Source dateFirst observed by CASCA
    FIRST EPSS

    EPSS score: 72.94% probability · 99.41th percentile

    Inspect raw assertion
    Field
    model_probability
    Value
    Probability 0.729360000000; percentile 0.994090000000
    Original evidence ↗
ExploitationCatalog member

CISA KEV · catalog date Mar 10, 2023 · first observed Jul 19, 2026

Exploit likelihood72.94%

FIRST EPSS · score date Aug 26, 2026 · 99.4th percentile · first observed Aug 26, 2026

SeverityCVSS 7.2

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

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Field
container
Value
CISA ADP Vulnrichment
Source dateSource date omittedFirst observed by CASCAOriginal evidence ↗
CVE ProgramDerivative copy
Record text

CVE Program Container

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Field
container
Value
CVE Program Container
Source dateSource date omittedFirst observed by CASCAOriginal evidence ↗
tenableOriginal assertion
Record text

Deserialization of Untrusted Data in Plex Media Server on Windows allows a remote, authenticated attacker to execute arbitrary Python code.

Inspect raw assertion
Field
container
Value
Deserialization of Untrusted Data in Plex Media Server on Windows allows a remote, authenticated attacker to execute arbitrary Python code.
Source dateSource date omittedFirst observed by CASCAOriginal evidence ↗
CISA KEVOriginal assertion
Exploitation cataloged

Plex Media Server Remote Code Execution Vulnerability

Inspect raw assertion
Field
observed_exploitation
Value
Plex Media Server Remote Code Execution Vulnerability
Source dateFirst observed by CASCAOriginal evidence ↗
FIRST EPSSOriginal assertion
EPSS score

72.94% probability · 99.41th percentile

Inspect raw assertion
Field
model_probability
Value
Probability 0.729360000000; percentile 0.994090000000
Source dateFirst observed by CASCAOriginal evidence ↗

Applicability

Cited product scope

Trace impact →
2Underlying assertions
2Canonical products
1Target assertions
1Constraint 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

3 scope groups

tenable · source assertedn/aPlex Media Server (Windows)Direct source scope
Affected: Versions prior to 1.19.3
Source-reported scope

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

Inspect raw assertion[{"status": "affected", "version": "Versions prior to 1.19.3"}]
NVD CPE · OPERATING SYSTEMmicrosoftwindowsEnvironmental constraint · 1 assertions
Version not applicableCanonical identity product-6a798dc931affc038ba266631a506d54b455ffebd96b4fae68f77b6bd7aef178Linked exact
Scope constrained
Inspect raw assertion
  1. cpe:2.3:o:microsoft:windows:-:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Environmental constraint
    Configuration
    0 · node/1 · match 0
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    a2572d17-1de6-457b-99cc-64afd54487ea
NVD CPE · APPLICATIONplexmedia_serverVulnerable target · 1 assertions
Any version (unconstrained) (< 1.19.3)Canonical identity product-93fcd9ba64f115d849b03e126a45c7e0871a948059899b4dab3156a341cc7157Linked exact
Scope supported
Inspect raw assertion
  1. cpe:2.3:a:plex:media_server:*:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 0
    Logic
    OR
    Version bounds
    through excluding 1.19.3
    Match ID
    3f0dcd61-6776-4b3b-978c-1e3f662d8b34

Affected-product evidence

Accepted scope and product mapping

1 canonical links · 1 source-reported links

Mapping establishedEvidence supported

vendor-56bda8bf06bb50f6f8934a0619366a60f16556b83eff0885f4c916dced06b62b · product-93fcd9ba64f115d849b03e126a45c7e0871a948059899b4dab3156a341cc7157

Source class
Nvd cpe vulnerable target
Assertions
1
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Aug 27, 2026
Retained assertion IDs
41ff240c-3832-4196-a0cf-0b4544c73362
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
a4ed7d1c-8fa3-4855-817e-9068dac07d71

Assessments

CVSS by origin

7.2
NVDCVSS 3.1 · role Primary · priority eligiblevalid_matchCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
6.5
NVDCVSS 2.0 · role Primary · priority eligiblevalid_matchAV:N/AC:L/Au:S/C:P/I:P/A:P
7.2
CVE Program sourceCVSS 3.1 · role Secondary · priority eligiblevalid_matchCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
7.2
CISA-ADPCVSS 3.1 · role unknown · display onlyDirect record assessment retained outside normalized eligibilityCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

Direct CVE/CNA normalized decisions

7.2Priority eligible

CISA-ADP

CVSS 3.1 · Secondary · Independent enrichment · rank 2

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
Validation
Valid match
Recomputed
7.2
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.