Vulnerability report

Trusted Third Party Report Confirmed Confidence In CISA KEV

CVE-2020-17519

Apache Flink Path Traversal

Apache Flink · 1.11.0 to <= 1.11.2

Watch CVE-2020-17519 Browse KEV feed
Severity
CVSS 7.5 · High
Confidence
Confirmed
Exploit status
Trusted Third Party Report
EPSS
98.0%
First observed
—
Last observed
—

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2020-17519 is an unauthenticated vulnerability affecting Apache Flink.

Have exploitation attempts been observed?

Yes. Exploitation attempts have been reported for this vulnerability. Previdian lists it as a known exploited vulnerability. Listed in CISA KEV. Also reported by third-party sources. Confidence is confirmed.

Who is affected?

Apache Flink, including 1.11.0 to <= 1.11.2 and Apache Flink 1.11.0 to 1.11.2.

What should we do?

Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.

Overview

Apache Flink Path Traversal

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.

apache Affected
flink
Through 1.11.2
Apache Software Foundation Affected
Apache Flink
Apache Flink 1.11.0 to 1.11.2
Published
05 Jan 2021
Exploitation Attempts Reported
23 May 2024
Attack vector
Remote
Complexity
Low
Privileges
None
User interaction
None

Tags

cisa apache nessus_scanner nuclei_scanner metasploit_scanner

CVE References

Exploitation evidence

Evidence of exploitation attempts

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploitation Attempts Observed in the Wild

CISA

Recorded 23 May 2024

A trusted third party reported exploitation attempts.

Proof of concept available

GitHub

Recorded 06 Jan 2021

Public scanner or PoC coverage increases practical exploitability.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the Previdian Pro API.

Learn about Pro API access
Source Added
CISA First 2024-05-23 00:00 UTC
The Shadowserver 2026-06-15 00:00 UTC

Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Virtual patch status

No Previdian virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

Learn about virtual patches →

Scanner Artifacts

Scanner and exploit-framework references linked to this CVE.

Scanner Reference Detected
Nuclei https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2020/CVE-2020-17519.yaml 25 Apr 2025
Nessus https://www.tenable.com/plugins/nessus/146314 08 Mar 2023
Metasploit https://github.com/rapid7/metasploit-framework/blob/master/modules/auxiliary/scanner/http/apache_flink_jobmanager_traversal.rb 05 Jan 2021

Risk and context

Severity, weaknesses, and research context

CVSS v3.1

7.5 High

Potential damage if exploited. Separate from whether attackers are using it.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

EPSS

98.0%

Estimated chance of exploitation in the next 30 days. Previdian's warning comes from evidence, not this score.

Weaknesses

Files or Directories Accessible to External Parties CWE-552

All CVSS Scores

CVSS v3.1 7.5 High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

CVSS v2.0 5.0 Medium

AV:N/AC:L/Au:N/C:P/I:N/A:N

Potential Proof of Concepts

These PoCs are unverified and could contain malware. Use at your own risk.

Apache Flink - Local File Inclusion

nuclei · Created Unknown

Timeline

From disclosure to observed exploitation attempts

  1. 00:00 UTC

    KEV confirmed by The Shadowserver

    Exploitation attempts reported by an external source

  2. 14:20 UTC

    Public PoC available

    Public proof-of-concept code published

  3. 00:00 UTC

    Nuclei template available

    Scanner coverage available

  4. 00:00 UTC

    Added to CISA KEV

    Listed in the CISA Known Exploited Vulnerabilities catalog

  5. 01:05 UTC

    Nessus plugin available

    Scanner coverage available

  6. 11:40 UTC

    CVE published

    Vulnerability disclosed publicly

  7. 00:00 UTC

    Metasploit module available

    Exploit module available

  8. 00:00 UTC

    CVE ID reserved

    Identifier reserved by the CNA

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

Start 14-day Pro trial Read API docs
  • Evidence confidence and provenance
  • First-party sensor telemetry
  • PoC and scanner references
  • Affected versions and enrichment
  • Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2020-17519

Sample API response 
{
  "cve_id": "CVE-2020-17519",
  "confidence": "Confirmed",
  "cvss_score": 7.5,
  "cvss_estimated": false,
  "epss_score": 0.98001,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": false
  },
  "sensor_telemetry": { "attempts": 0, "sensors": 0 }
}