CASCACascade Atlas

Evidence dossier

CVE-2020-17519

Apache Flink directory traversal attack: reading remote files through the REST API

Exploited in the wild (CISA KEV since May 23, 2024). NVD reports CVSS 3.1 7.5. Severity assessments differ within at least one CVSS version. EPSS estimates 97.9% exploit likelihood as of Aug 27, 2026.

81.2–87.8Priority evidence range
Evidence current through Aug 27, 2026, 6:09 PM UTC

As of Aug 27, 2026

Normalized restatement

A change introduced in Apache Flink 1.11.0 (and released in 1.11.1 and 1.11.2 as well) allows attackers to read any file on the local filesystem of the JobManager through the REST interface of the JobManager process. Access is restricted to files accessible by the JobManager process. All users should upgrade to Flink 1.11.3 or 1.12.0 if their Flink instance(s) are exposed. The issue was fixed in commit b561010b0ee741543c3953306037f00d7a9f0801 from apache/flink:master.

State
PUBLISHED
Published
Jan 5, 2021
Updated
Oct 21, 2025
Evidence coverage
77%

Evidence chronology

What was known when

Download this view's receipt →
  1. Source dateSource date omittedFirst observed by CASCA
    apache

    Record text: Apache Flink directory traversal attack: reading remote files through the REST API

    Inspect raw assertion
    Field
    container
    Value
    Apache Flink directory traversal attack: reading remote files through the REST API
    Original evidence ↗
  2. 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 ↗
  3. 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 ↗
  4. Source dateFirst observed by CASCA
    CISA KEV

    Exploitation cataloged: Apache Flink Improper Access Control Vulnerability

    Inspect raw assertion
    Field
    observed_exploitation
    Value
    Apache Flink Improper Access Control Vulnerability
    Original evidence ↗
  5. Source dateFirst observed by CASCA
    FIRST EPSS

    EPSS score: 97.86% probability · 99.9th percentile

    Inspect raw assertion
    Field
    model_probability
    Value
    Probability 0.978560000000; percentile 0.999030000000
    Original evidence ↗

Assessments differ

NVD7.5CVSS 3.1 · source date omitted
NVD5.0CVSS 2.0 · source date omitted
CVE Program source9.1CVSS 3.1 · source date omitted

Values are shown separately by source and CVSS version.

ExploitationCatalog member

CISA KEV · catalog date May 23, 2024 · first observed Jul 19, 2026

Exploit likelihood97.86%

FIRST EPSS · score date Aug 27, 2026 · 99.9th 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

apacheOriginal assertion
Record text

Apache Flink directory traversal attack: reading remote files through the REST API

Inspect raw assertion
Field
container
Value
Apache Flink directory traversal attack: reading remote files through the REST API
Source dateSource date omittedFirst observed by CASCAOriginal evidence ↗
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 ↗
CISA KEVOriginal assertion
Exploitation cataloged

Apache Flink Improper Access Control Vulnerability

Inspect raw assertion
Field
observed_exploitation
Value
Apache Flink Improper Access Control Vulnerability
Source dateFirst observed by CASCAOriginal evidence ↗
FIRST EPSSOriginal assertion
EPSS score

97.86% probability · 99.9th percentile

Inspect raw assertion
Field
model_probability
Value
Probability 0.978560000000; percentile 0.999030000000
Source dateFirst observed by CASCAOriginal evidence ↗

Applicability

Cited product scope

Trace impact →
1Underlying assertions
1Canonical products
1Target 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

3 scope groups

CISA-ADP · source assertedapacheflinkDirect source scope
Affected: 1.11.0 through 1.11.2 (semver comparison)
Source-reported scope

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

Inspect raw assertion[{"status": "affected", "version": "1.11.0", "versionType": "semver", "lessThanOrEqual": "1.11.2"}]
apache · source assertedApache Software FoundationApache FlinkDirect source scope
Affected: Apache Flink 1.11.0 to 1.11.2
Source-reported scope

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

Inspect raw assertion[{"status": "affected", "version": "Apache Flink 1.11.0 to 1.11.2"}]
NVD CPE · APPLICATIONapacheflinkVulnerable target · 1 assertions
Any version (unconstrained) (>= 1.11.0, < 1.11.3)Canonical identity product-5855e3448cfcc0a85406f6c67b6e54fbceb78ce102ff4ed13af10479d3f8410dLinked exact
Scope supported
Inspect raw assertion
  1. cpe:2.3:a:apache:flink:*:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 0
    Logic
    OR
    Version bounds
    from including 1.11.0; through excluding 1.11.3
    Match ID
    17dbfdc8-023d-4816-97ab-88f17abb2cfc

Affected-product evidence

Accepted scope and product mapping

1 canonical links · 1 source-reported links

Mapping establishedEvidence supported

vendor-8771dac0ae5eeec984ca23e4bbe5a243fb7896ad7c1c4afc6acd3abe53fdd152 · product-5855e3448cfcc0a85406f6c67b6e54fbceb78ce102ff4ed13af10479d3f8410d

Source class
Nvd cpe vulnerable target
Assertions
1
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Aug 27, 2026
Retained assertion IDs
6793b3bb-7306-4cc7-a763-dae1b236d40f
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
2
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Aug 27, 2026
Retained assertion IDs
6f1349f3-7c5f-407e-9817-cff49ff261ffcceb93f8-382e-412b-9a8a-cc3a6223f502

Assessments

CVSS by origin

7.5
NVDCVSS 3.1 · role Primary · priority eligiblevalid_matchCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
5.0
NVDCVSS 2.0 · role Primary · priority eligiblevalid_matchAV:N/AC:L/Au:N/C:P/I:N/A:N
9.1
CVE Program sourceCVSS 3.1 · role Secondary · priority eligiblevalid_matchCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
9.1
CISA-ADPCVSS 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:N/A:H

Direct CVE/CNA normalized decisions

9.1Priority eligible

CISA-ADP

CVSS 3.1 · Secondary · Independent enrichment · rank 2

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Validation
Valid match
Recomputed
9.1
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.