How severe is CVE-2020-17519?

CVE-2020-17519 has a CVSS score of 7.5/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2020-17519?

CVE-2020-17519 affects the following packages: org.apache.flink:flink-runtime_2.11 (Maven), org.apache.flink:flink-runtime_2.12 (Maven). Ecosystems affected: Maven.

How do I fix CVE-2020-17519?

Update org.apache.flink:flink-runtime_2.11 to 1.11.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-17519 is resolved across your whole dependency graph.

How do I detect CVE-2020-17519 in my Maven dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.apache.flink:flink-runtime_2.11, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2020-17519 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2020-17519 actively exploited in the wild?

Yes. There are 15 known exploit references for CVE-2020-17519, including 1 documented proof-of-concept exploit on Exploit-DB and 10 in-the-wild exploitations observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2020-17519?

CVE-2020-17519 has an EPSS (Exploit Prediction Scoring System) score of 97.8%, placing it in the 100th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. A score above 50% indicates significantly elevated exploitation risk — immediate patching is strongly recommended.

Is CVE-2020-17519 in the CISA Known Exploited Vulnerabilities catalog?

Yes. CVE-2020-17519 (Apache Flink Improper Access Control Vulnerability) was added to CISA's Known Exploited Vulnerabilities (KEV) catalog on 2024-05-23. CISA required all US federal civilian agencies to remediate this vulnerability by 2024-06-13. The required action was: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable. Being listed in the KEV catalog is the strongest possible confirmation of active exploitation — treat this as a critical priority.

What type of vulnerability is CVE-2020-17519?

CVE-2020-17519 is classified as CWE-552 (CWE-552). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

Is there exploit tooling available for CVE-2020-17519?

A Nuclei detection template exists for CVE-2020-17519, meaning automated scanners can fingerprint it. A Metasploit module references CVE-2020-17519, which lowers the barrier to weaponization. Public exploit tooling significantly increases real-world risk — prioritize patching and ensure detection coverage. Exploit tooling should only ever be used in isolated, authorized testing environments.

When was CVE-2020-17519 published, and has it been updated?

CVE-2020-17519 was published on January 5, 2021 and was last updated on October 24, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕

☕ Maven

CISA KEV · ACTIVELY EXPLOITED

HIGH severity

CVE-2020-17519 — flink-runtime_2.11

HIGH

CVE-2020-17519 is a high-severity (CVSS 7.5) CWE-552 vulnerability in org.apache.flink:flink-runtime_2.11. It is in CISA's Known Exploited Vulnerabilities catalog (added 2024-05-23) — treat it as actively exploited and patch now. A fix is available for org.apache.flink:flink-runtime_2.11 — see the affected versions and patch details below.

Path Traversal in Apache Flink

Also known asBIT-flink-2020-17519GHSA-395w-qhqr-9fr6

Published

Jan 5, 2021

Updated

Oct 24, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

15 known

Exploitation data as of Oct 23, 2026 · OSV.dev, NVD, CISA KEV, FIRST.org (EPSS)

Exploitation Status

Actively exploited in the wild

Confirmed by CISA's Known Exploited Vulnerabilities catalog on 2024-05-23. Federal agencies were required to remediate by 2024-06-13.
CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.

Exploitation and automatability from CISA (KEV catalog and SSVC triage) for CVE-2020-17519.

EPSS Exploitation Probability

via FIRST.org ↗

97.8%probability of exploitation in next 30 days

Very High Risk0.00%

Lower risk than most CVEs100th percentile — riskier than 100% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2020-17519 by exploitation likelihood (EPSS) against impact (CVSS). In the shaded patch-first corner (EPSS 50%+, CVSS 7.0+).

Where this sits among everything scored

Of 394,803 CVEs with a current EPSS score, this one falls in the ≥ 90% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

2 pkgs affected

☕org.apache.flink:flink-runtime_2.11☕org.apache.flink:flink-runtime_2.12

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

Description

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.

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`org.apache.flink:flink-runtime_2.11`	≥ 1.11.0&&< 1.11.3	1.11.3`org.apache.flink:flink-runtime_2.11:1.11.3`
☕Maven	`org.apache.flink:flink-runtime_2.12`	≥ 1.11.0&&< 1.11.3	1.11.3`org.apache.flink:flink-runtime_2.12:1.11.3`

Affected Products

1 product · 1 configurations

Application

flinkapache

≥ 1.11.0 && < 1.11.3

range

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

EDB-49398webappsjava✓ Verified

Apache Flink 1.11.0 - Unauthenticated Arbitrary File Read (Metasploit)

by SunCSR Team · Jan 8, 2021

Exploit-DB Source

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.apache.flink:flink-runtime_2.11, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.apache.flink:flink-runtime_2.11 to 1.11.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-17519 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How to detect CVE-2020-17519

A community-maintained Nuclei template exists for this CVE. You can scan for it directly:

nuclei -id cve-2020-17519 -u https://target

Template: Apache Flink - Local File Inclusion
Severity: high
Impact: Unauthenticated attackers can read arbitrary files from the JobManager local filesystem, potentially exposing sensitive configuration files, credentials, and proprietary data.
Remediation: Apply the latest security patches or upgrade to a patched version of Apache Flink to mitigate the vulnerability.

Template by ProjectDiscovery nuclei-templates (pdteam), MIT licensed. View the full template. Scan only systems you are authorised to test.

Frequently Asked Questions

O3 Security · Impact-Aware SCA

Is CVE-2020-17519 in your dependencies?

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