Skip to content
Weekly Signal
Live intelligence Updated 20 Aug 2026 · 12:21 UTC

Apache · Flink

CVE-2020-17519

Apache Flink Improper Access Control Vulnerability

Recommended action

Validate affected assets and exposure now, then remediate on an accelerated schedule. Vendor advisory from lists.apache.org

View response plan
CVSS7.5
EPSS97.9%
KEVYes
ExploitationConfirmed exploitation
RemediationNot yet verified ↓

Assessment

Why it matters

CISA lists this vulnerability as known to be exploited; exploitation is confirmed; EPSS is 97.9%; technical severity is CVSS 7.5.

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.

Who should care

  • Teams operating Flink
  • Vulnerability and exposure management teams
  • Security operations teams monitoring exploitation activity

Response plan

What I would do

  1. Confirm whether Flink is present in the environment.
  2. Identify affected versions and establish whether vulnerable services are exposed or reachable.
  3. Vendor advisory from lists.apache.org
  4. Review relevant security telemetry for evidence of attempted or successful exploitation.
  5. Document the remediation decision and track it to verified completion.

Treatment intelligence

Remediation intelligence

Not yet verified

Vendor sources are listed before government and third-party guidance. Confirm product applicability and change prerequisites before deployment.

Verification noteAutomated link verification has not completed for this guidance yet.

Required Action

Technical details

CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
CWE
CWE-552
Affected versions
Apache Flink (Start Including 1.11.0, End Excluding 1.11.3)
Fixed versions
Apache Flink (Fixed from 1.11.3)
Published
5 January 2021
Attack vector
Network
Privileges required
None
User interaction
None

Signal timeline

  1. CVE published
  2. Added to CISA KEV
  3. Latest EPSS score: 97.9%
  4. Signal calculated at 82

External references

Live public intelligence This assessment combines public-source evidence. Validate the affected product, version and exposure against your own environment before making a risk decision.