CASCACascade Atlas

Evidence dossier

CVE-2023-40044

WS_FTP Server Ad Hoc Transfer Module .NET Deserialization Vulnerability

Exploited in the wild (CISA KEV since Oct 5, 2023). NVD reports CVSS 3.1 8.8. Severity assessments differ within at least one CVSS version. EPSS estimates 90.1% exploit likelihood as of Aug 27, 2026.

83.6–88.2Priority evidence range
Evidence current through Aug 27, 2026, 6:09 PM UTC

As of Aug 27, 2026

Normalized restatement

In WS_FTP Server versions prior to 8.7.4 and 8.8.2, a pre-authenticated attacker could leverage a .NET deserialization vulnerability in the Ad Hoc Transfer module to execute remote commands on the underlying WS_FTP Server operating system.

State
PUBLISHED
Published
Sep 27, 2023
Updated
Oct 21, 2025
Evidence coverage
82%

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
    ProgressSoftware

    Record text: WS_FTP Server Ad Hoc Transfer Module .NET Deserialization Vulnerability

    Inspect raw assertion
    Field
    container
    Value
    WS_FTP Server Ad Hoc Transfer Module .NET Deserialization Vulnerability
    Original evidence ↗
  4. Source dateFirst observed by CASCA
    CISA KEV

    Exploitation cataloged: Progress WS_FTP Server Deserialization of Untrusted Data Vulnerability

    Inspect raw assertion
    Field
    observed_exploitation
    Value
    Progress WS_FTP Server Deserialization of Untrusted Data Vulnerability
    Original evidence ↗
  5. Source dateFirst observed by CASCA
    FIRST EPSS

    EPSS score: 90.15% probability · 99.79th percentile

    Inspect raw assertion
    Field
    model_probability
    Value
    Probability 0.901500000000; percentile 0.997860000000
    Original evidence ↗

Assessments differ

NVD8.8CVSS 3.1 · source date omitted
security@progress.com10.0CVSS 3.1 · source date omitted

Values are shown separately by source and CVSS version.

ExploitationCatalog member

CISA KEV · catalog date Oct 5, 2023 · first observed Jul 19, 2026

Exploit likelihood90.15%

FIRST EPSS · score date Aug 27, 2026 · 99.8th percentile · first observed Aug 27, 2026

SeverityAssessments differ

NVD · 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 ↗
ProgressSoftwareOriginal assertion
Record text

WS_FTP Server Ad Hoc Transfer Module .NET Deserialization Vulnerability

Inspect raw assertion
Field
container
Value
WS_FTP Server Ad Hoc Transfer Module .NET Deserialization Vulnerability
Source dateSource date omittedFirst observed by CASCAOriginal evidence ↗
CISA KEVOriginal assertion
Exploitation cataloged

Progress WS_FTP Server Deserialization of Untrusted Data Vulnerability

Inspect raw assertion
Field
observed_exploitation
Value
Progress WS_FTP Server Deserialization of Untrusted Data Vulnerability
Source dateFirst observed by CASCAOriginal evidence ↗
FIRST EPSSOriginal assertion
EPSS score

90.15% probability · 99.79th percentile

Inspect raw assertion
Field
model_probability
Value
Probability 0.901500000000; percentile 0.997860000000
Source dateFirst observed by CASCAOriginal evidence ↗

Applicability

Cited product scope

Trace impact →
2Underlying assertions
1Canonical products
2Target 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

2 scope groups

ProgressSoftware · source assertedProgress Software CorporationWS_FTP ServerDirect source scope
Affected: 8.8.0 to before 8.8.2 (semver comparison)Affected: 8.7.0 to before 8.7.4 (semver comparison)
Source-reported scope

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

Inspect raw assertion[{"status": "affected", "version": "8.8.0", "lessThan": "8.8.2", "versionType": "semver"}, {"status": "affected", "version": "8.7.0", "lessThan": "8.7.4", "versionType": "semver"}]
NVD CPE · APPLICATIONprogressws_ftp_serverVulnerable target · 2 assertions
Any version (unconstrained) (< 8.7.4); Any version (unconstrained) (>= 8.8, < 8.8.2)Canonical identity product-1f22fc93d8d81fdd39691f0e8fca1962fbf5c2e465010c0c30f81e86565a84a2Linked exact
Scope supported
Inspect raw assertions
  1. cpe:2.3:a:progress:ws_ftp_server:*:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 1
    Logic
    OR
    Version bounds
    from including 8.8; through excluding 8.8.2
    Match ID
    670aeeb3-b2b3-41da-8188-4f1a4e02f0ad
  2. cpe:2.3:a:progress:ws_ftp_server:*:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 0
    Logic
    OR
    Version bounds
    through excluding 8.7.4
    Match ID
    443ccfde-4a61-40f1-96c1-b36bf9240773

Affected-product evidence

Accepted scope and product mapping

1 canonical links · 1 source-reported links

Mapping establishedEvidence supported

vendor-119080fac24ac591a2622fbe428dbad84319550770d0feb834d70fb96b32a742 · product-1f22fc93d8d81fdd39691f0e8fca1962fbf5c2e465010c0c30f81e86565a84a2

Source class
Nvd cpe vulnerable target
Assertions
2
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Aug 27, 2026
Retained assertion IDs
400d8789-3dd0-4729-bed6-3297b4fae356cf430757-b360-4312-920f-a4f65552577f
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
15f200d5-f68e-45a5-aec1-0be32a0df470

Assessments

CVSS by origin

8.8
NVDCVSS 3.1 · role Primary · priority eligiblevalid_matchCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
10.0
security@progress.comCVSS 3.1 · role Secondary · priority eligiblevalid_matchCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
10.0
ProgressSoftwareCVSS 3.1 · role unknown · display onlyDirect record assessment retained outside normalized eligibilityCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Direct CVE/CNA normalized decisions

10.0Priority eligible

ProgressSoftware

CVSS 3.1 · Primary · Original assertion · rank 1

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Validation
Valid match
Recomputed
10.0
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.