---
title: "CVE-2020-17519: Apache Flink Improper Access Control Vulnerability"
url: https://erroneo.us/security/cve/CVE-2020-17519/
description: "CVE-2020-17519 (Apache Flink): Exploited in the wild (CISA KEV). A change introduced in Apache Flink 1.11.0 (and released in 1.11.1 and 1.11.2 as well)…"
type: vulnerability-record
section: "Security Digest"
date_published: 2021-01-05
date_modified: 2025-10-21
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2020-17519"
kev: true
cvss: 9.1
epss: 0.97809
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2020-17519: Apache Flink Improper Access Control Vulnerability

**Signal:** Exploited: patch now if you run it. CISA has confirmed exploitation in the wild. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Yes, if you run Apache Flink. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2024-05-23, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2024-06-13 ; treat that as the outer limit, not the target.
- EPSS 97.8% , percentile 99.9: FIRST’s model estimates a 97.8% chance of exploitation activity in the next 30 days, higher than 99.9% of all scored CVEs (very high). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.

## What it is

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 products (CVE record)

- Apache Software Foundation Apache Flink: Apache Flink 1.11.0 to 1.11.2

## Severity

- CISA-ADP CVSS 3.1: 9.1 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H`

## Exploitation

- CISA KEV: added 2024-05-23; federal due date 2024-06-13. Known ransomware use: Unknown.
- CISA required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
- CISA SSVC assessment: exploitation active , automatable yes , technical impact partial .
- FIRST EPSS (model of 2026-10-21): 97.81% probability of exploitation activity in the next 30 days; percentile 99.9.

## Sources

- [Listed in CISA KEV notes (lists.apache.org)](https://lists.apache.org/thread/typ0h03zyfrzjqlnb7plh64df1g2383d)
- [CVE.org record CVE-2020-17519](https://www.cve.org/CVERecord?id=CVE-2020-17519)
- [NVD entry CVE-2020-17519](https://nvd.nist.gov/vuln/detail/CVE-2020-17519)
- [CISA Known Exploited Vulnerabilities catalog entry](https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-17519)
- [lists.apache.org](https://lists.apache.org/thread.html/r6843202556a6d0bce9607ebc02e303f68fc88e9038235598bde3b50d%40%3Cdev.flink.apache.org%3E)
- [[flink-user] 20210105 [CVE-2020-17519] Apache Flink directory traversal attack: reading remote files through the REST API](https://lists.apache.org/thread.html/r6843202556a6d0bce9607ebc02e303f68fc88e9038235598bde3b50d%40%3Cuser.flink.apache.org%3E)
- [[announce] 20210105 [CVE-2020-17519] Apache Flink directory traversal attack: reading remote files through the REST API](https://lists.apache.org/thread.html/r6843202556a6d0bce9607ebc02e303f68fc88e9038235598bde3b50d%40%3Cannounce.apache.org%3E)
- [[oss-security] 20210105 [CVE-2020-17519] Apache Flink directory traversal attack: reading remote files through the REST API](http://www.openwall.com/lists/oss-security/2021/01/05/2)
- [[flink-issues] 20210106 [GitHub] [flink-web] zentol commented on a change in pull request #408: Add security page for Flink](https://lists.apache.org/thread.html/r28f17e564950d663e68cc6fe75756012dda62ac623766bb9bc5e7034%40%3Cissues.flink.apache.org%3E)
- [packetstormsecurity.com](http://packetstormsecurity.com/files/160849/Apache-Flink-1.11.0-Arbitrary-File-Read-Directory-Traversal.html)
- [[flink-issues] 20210110 [jira] [Updated] (FLINK-20916) Typo in test for CVE-2020-17519](https://lists.apache.org/thread.html/r2fc60b30557e4a537c2a6293023049bd1c49fd92b518309aa85a0398%40%3Cissues.flink.apache.org%3E)
- [[flink-dev] 20210110 [jira] [Created] (FLINK-20916) Typo in test for CVE-2020-17519](https://lists.apache.org/thread.html/r4e1b72bfa789ea5bc20b8afe56119200ed25bdab0eb80d664fa5bfe2%40%3Cdev.flink.apache.org%3E)
- [[flink-issues] 20210110 [jira] [Created] (FLINK-20916) Typo in test for CVE-2020-17519](https://lists.apache.org/thread.html/r0a433be10676f4fe97ca423d08f914e0ead341c901216f292d2bbe83%40%3Cissues.flink.apache.org%3E)
- [[flink-issues] 20210111 [jira] [Assigned] (FLINK-20916) Typo in test for CVE-2020-17519](https://lists.apache.org/thread.html/r88b55f3ebf1f8f4e1cc61f030252aaef4b77060b56557a243abb92a1%40%3Cissues.flink.apache.org%3E)
- [[flink-issues] 20210111 [jira] [Commented] (FLINK-20916) Typo in test for CVE-2020-17519](https://lists.apache.org/thread.html/r88f427865fb6aa6e6378efe07632a1906b430365e15e3b9621aabe1d%40%3Cissues.flink.apache.org%3E)
- [[flink-dev] 20210113 Re: [DISCUSS] Releasing Apache Flink 1.10.3](https://lists.apache.org/thread.html/ra8c96bf3ccb4e491f9ce87ba35f134b4449beb2a38d1ce28fd89001f%40%3Cdev.flink.apache.org%3E)
- [[flink-dev] 20210115 Re: [DISCUSS] Releasing Apache Flink 1.10.3](https://lists.apache.org/thread.html/r229167538863518738e02f4c1c5a8bb34c1d45dadcc97adf6676b0c1%40%3Cdev.flink.apache.org%3E)
- [[announce] 20210125 Apache Software Foundation Security Report: 2020](https://lists.apache.org/thread.html/r90890afea72a9571d666820b2fe5942a0a5f86be406fa31da3dd0922%40%3Cannounce.apache.org%3E)
- [[announce] 20210223 Re: Apache Software Foundation Security Report: 2020](https://lists.apache.org/thread.html/r1125f3044a0946d1e7e6f125a6170b58d413ebd4a95157e4608041c7%40%3Cannounce.apache.org%3E)
- [lists.apache.org](https://lists.apache.org/thread.html/r26fcdd4fe288323006253437ebc4dd6fdfadfb5e93465a0e4f68420d%40%3Cuser-zh.flink.apache.org%3E)

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Source page: https://erroneo.us/security/cve/CVE-2020-17519/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt