dbcve.org
Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 13 Jun 2024.
FlinkApplication · Apache

CVE-2020-17519

HIGH · 7.5 CVSS v3.1 Published 2021-01-05
Fix available
A fix is available. Upgrade to 1.11.3 or later.
See remediation →
100/100
Remediation priority · Urgent
In the wild High EPSS Public exploit Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A path traversal vulnerability in Apache Flink's JobManager REST interface (introduced in version 1.11.0) allows remote attackers to read arbitrary files from the local filesystem via specially crafted HTTP requests. The vulnerability is exploitable without authentication when the REST interface is exposed.

MitigationUpgrade Apache Flink to version 1.11.3 or 1.12.0. If immediate upgrade is not feasible, ensure the JobManager REST interface is not exposed to untrusted networks or is protected by network segmentation/authentication.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
FlinkApplication
Affected:>= 1.11.0, < 1.11.3

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify Flink version
    Run 'flink --version' from the Flink installation bin directory, or check the flink-dist/target directory, or inspect the pom.xml in the Flink source if available. Also check the JobManager logs for the version string at startup.
    Affected if The version is 1.11.0, 1.11.1, or 1.11.2
  2. Locate Flink configuration file
    Find the flink-conf.yaml file in the Flink installation under the conf/ directory, or check /etc/flink/ on some installations.
    Affected if Configuration file exists and REST interface settings can be inspected
  3. Verify REST interface binding address
    In flink-conf.yaml, look for the 'rest.bind-address' or 'rest.address' settings. Check if the JobManager REST endpoint is bound to 0.0.0.0 (all interfaces) or a public IP address rather than 127.0.0.1 (localhost only).
    Affected if REST interface is bound to 0.0.0.0 or a non-loopback address, exposing it to network access
  4. Confirm REST port is accessible externally
    Run 'netstat -tlnp | grep <rest-port>' or 'ss -tlnp | grep <rest-port>' where the rest.port setting from flink-conf.yaml (default 8081) is the port number. Verify the listening address is not 127.0.0.1.
    Affected if The REST port listens on 0.0.0.0 or an external IP rather than 127.0.0.1

You are affected if you are running Apache Flink version 1.11.0, 1.11.1, or 1.11.2 with the REST interface exposed to untrusted networks (bound to 0.0.0.0 or a public IP rather than localhost).

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 1.11.3 or later
Fixed in 1.11.3
Interim mitigation

Upgrade Apache Flink to version 1.11.3 or 1.12.0. If immediate upgrade is not feasible, ensure the JobManager REST interface is not exposed to untrusted networks or is protected by network segmentation/authentication.

Recommended fix High confidence

Flink 1.11.3 or 1.12.0

  1. Identify all Flink deployments running version 1.11.0, 1.11.1, or 1.11.2 with the REST interface exposed
  2. Schedule a maintenance window for the upgrade
  3. Backup all Flink configurations, jobs, and application state
  4. Upgrade Apache Flink to version 1.11.3 or 1.12.0 using the official upgrade procedure
  5. After upgrade, verify the REST interface is functioning correctly and the vulnerability is patched
  6. If using Flink 1.12.0, review the 1.12.0 release notes for any migration considerations

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Flink Exploited in the wild — priority engagement
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,080
Get it fixed fast

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,328.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2020-17519 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2020-17519 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data