CVE-2020-17518: Flink runtime Upload Of File To Arbitrary Vulnerability

Q: What is CVE-2020-17518?

CVE-2020-17518 is a security vulnerability in Flink runtime involving Upload of file to arbitrary path in Apache Flink under CWE-23: Relative Path Traversal.

Q: Which Flink runtime versions are affected?

Affected versions include releases prior to 1.11.3 across affected packages: org.apache.flink:flink-runtime.

Q: What version fixes CVE-2020-17518?

Upgrading to 1.11.3 (or the latest patched release for your respective branch) resolves the vulnerability.

Q: Is flink-runtime affected?

Yes, org.apache.flink:flink-runtime is affected in releases prior to 1.11.3. Upgrade your dependency to 1.11.3 or later.

Q: What is the CVSS score of CVE-2020-17518?

CVE-2020-17518 has a CVSS v3.1 base score of 7.5 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.

Q: What CWE is associated with CVE-2020-17518?

CVE-2020-17518 is classified under CWE-23: Relative Path Traversal (The product uses external input to construct a pathname that should be within a restricted directory, but it does not properly neutralize sequences such as ".." that can resolve to a location that is outside of that directory.).

Q: How can I check Maven dependencies for CVE-2020-17518?

Run the dependency tree command: 'mvn dependency:tree -Dincludes=org.apache.flink'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.

HIGH

Advisory Identifier: GHSA-7q5g-gph2-4rc6

CVSS 7.5

CWE-23 CWE-22

Published 2022-02-09

Advisory Summary

CVE-2020-17518 is a HIGH (CVSS 7.5) upload of file to arbitrary vulnerability (CWE-23: Relative Path Traversal) affecting Flink runtime libraries in the Maven ecosystem. The issue involves upload of file to arbitrary path in apache flink. Remediation is available by upgrading affected packages to version 1.11.3.

CVE-2020-17518 at a Glance

CVE Identifier CVE-2020-17518

GHSA Identifier GHSA-7q5g-gph2-4rc6

Severity HIGH

CVSS v3.1 Base Score 7.5

CWE Classification CWE-23: Relative Path Traversal

Affected Product Flink runtime

Package Ecosystem Maven

Published Date 2022-02-09

Last Updated 2021-04-07

Security Impact

CVSS: 7.5

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N).

Attack Vector Network (AV:N)

Attack Complexity Low (AC:L)

Privileges Required None (PR:N)

User Interaction None (UI:N)

Scope Unchanged (S:U)

Confidentiality None (C:N)

Integrity High (I:H)

Availability None (A:N)

How to Fix CVE-2020-17518

To remediate this vulnerability, upgrade all affected Flink runtime dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

org.apache.flink:flink-runtime fixed: 1.11.3

<dependency>
    <groupId>org.apache.flink</groupId>
    <artifactId>flink-runtime</artifactId>
    <version>1.11.3</version>
</dependency>

Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release:

mvn dependency:tree -Dincludes=org.apache.flink

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2020-17518, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree -Dincludes=org.apache.flink

Analyze the terminal output to locate any version of Flink runtime in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.11.3), your application is affected.

Note: The mvn dependency:tree -Dincludes=org.apache.flink command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-23: Relative Path Traversal, where the product uses external input to construct a pathname that should be within a restricted directory, but it does not properly neutralize sequences such as ".." that can resolve to a location that is outside of that directory. In Flink runtime, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

Apache Flink 1.5.1 introduced a REST handler that allows you to write an uploaded file to an arbitrary location on the local file system, through a maliciously modified HTTP HEADER. The files can be written to any location accessible by Flink 1.5.1. 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 a5264a6f41524afe8ceadf1d8ddc8c80f323ebc4 from apache/flink:master.

CVE-2020-17518 Affected Flink runtime Versions

1 component(s)

Fixed Versions:

1.11.3

Product / Package	Ecosystem	Affected Versions	Fixed Version
org.apache.flink:flink-runtime maven/org.apache.flink/flink-runtime	Maven	≥ 1.5.1 < 1.11.3	1.11.3

References

NVD — CVE-2020-17518 NVD

https://nvd.nist.gov/vuln/detail/CVE-2020-17518

Security Fix Commit FIX COMMIT

https://github.com/apache/flink/commit/a5264a6f41524afe8ceadf1d8ddc8c80f323ebc4

lists.apache.org/thread.html/rfe159c... WEB

https://lists.apache.org/thread.html/rfe159ccf496d75813f24c6079c5d33872d83f5a2e39cb32c3aef5a73@%3Cissues.flink.apache.org%3E

lists.apache.org/thread.html/rf8812a... WEB

https://lists.apache.org/thread.html/rf8812a5703f4a5f1341138baf239258b250875699732cfdf9d55b21d@%3Cissues.flink.apache.org%3E

lists.apache.org/thread.html/rec0d65... WEB

https://lists.apache.org/thread.html/rec0d650fbd4ea1a5e1224a347d83a63cb44291c334ad58b8809bc23b@%3Cissues.flink.apache.org%3E

lists.apache.org/thread.html/rd6a1a0... WEB

https://lists.apache.org/thread.html/rd6a1a0e2d73220a65a8f6535bbcd24bb66adb0d046c4a1aa18777cf3@%3Cdev.flink.apache.org%3E

lists.apache.org/thread.html/rd24673... WEB

https://lists.apache.org/thread.html/rd2467344f88bcaf108b8209ca92da8ec393c68174bfb8c27d1e20faa@%3Cdev.flink.apache.org%3E

lists.apache.org/thread.html/rcb9e8a... WEB

https://lists.apache.org/thread.html/rcb9e8af775f2a3706b69153aefde78f208871649df057c70ce2e24f9@%3Cissues.flink.apache.org%3E

lists.apache.org/thread.html/rb43cd4... WEB

https://lists.apache.org/thread.html/rb43cd476419a48be89c1339b527a18116f23eec5b6df2b2acbfef261@%3Cuser.flink.apache.org%3E

lists.apache.org/thread.html/rb43cd4... WEB

https://lists.apache.org/thread.html/rb43cd476419a48be89c1339b527a18116f23eec5b6df2b2acbfef261@%3Cdev.flink.apache.org%3E

lists.apache.org/thread.html/rb43cd4... WEB

https://lists.apache.org/thread.html/rb43cd476419a48be89c1339b527a18116f23eec5b6df2b2acbfef261@%3Cannounce.apache.org%3E

lists.apache.org/thread.html/rb43cd4... WEB

https://lists.apache.org/thread.html/rb43cd476419a48be89c1339b527a18116f23eec5b6df2b2acbfef261%40%3Cdev.flink.apache.org%3E

lists.apache.org/thread.html/ra8c96b... WEB

https://lists.apache.org/thread.html/ra8c96bf3ccb4e491f9ce87ba35f134b4449beb2a38d1ce28fd89001f@%3Cdev.flink.apache.org%3E

lists.apache.org/thread.html/r90890a... WEB

https://lists.apache.org/thread.html/r90890afea72a9571d666820b2fe5942a0a5f86be406fa31da3dd0922@%3Cannounce.apache.org%3E

lists.apache.org/thread.html/r88200d... WEB

https://lists.apache.org/thread.html/r88200d2f0b620c6b4b1585a7171355005c89e678b01d0e71a16c57e7@%3Cissues.flink.apache.org%3E

lists.apache.org/thread.html/r8167f3... WEB

https://lists.apache.org/thread.html/r8167f30c4c60a11b8d5be3f55537beeda629be61196e693bde403b36@%3Cissues.flink.apache.org%3E

lists.apache.org/thread.html/r7b2ee8... WEB

https://lists.apache.org/thread.html/r7b2ee88c66fc1d0823e66475631f5c3e7f0365204ff0cb094d9f2433@%3Cissues.flink.apache.org%3E

lists.apache.org/thread.html/r710693... WEB

https://lists.apache.org/thread.html/r710693b0d3b229c81f485804ea1145b4edda79c9e77d66c39a0a2ff1@%3Cissues.flink.apache.org%3E

lists.apache.org/thread.html/r705fb2... WEB

https://lists.apache.org/thread.html/r705fb2211b82c9f1f8d2b1d4c823bcbca50402ba09b96608ec657efe@%3Cissues.flink.apache.org%3E

lists.apache.org/thread.html/r5444ac... WEB

https://lists.apache.org/thread.html/r5444acac3407ef6397d6aef1b5aec2db53b4b88ef221e63084c1e5f2@%3Cissues.flink.apache.org%3E

lists.apache.org/thread.html/r4a8783... WEB

https://lists.apache.org/thread.html/r4a87837518804b31eb9db3048347ed2bb7b46fbaad5844f22a9fd4dc@%3Cissues.flink.apache.org%3E

lists.apache.org/thread.html/r28f17e... WEB

https://lists.apache.org/thread.html/r28f17e564950d663e68cc6fe75756012dda62ac623766bb9bc5e7034@%3Cissues.flink.apache.org%3E

lists.apache.org/thread.html/r26fcdd... WEB

https://lists.apache.org/thread.html/r26fcdd4fe288323006253437ebc4dd6fdfadfb5e93465a0e4f68420d@%3Cuser-zh.flink.apache.org%3E

lists.apache.org/thread.html/r229167... WEB

https://lists.apache.org/thread.html/r229167538863518738e02f4c1c5a8bb34c1d45dadcc97adf6676b0c1@%3Cdev.flink.apache.org%3E

lists.apache.org/thread.html/r1125f3... WEB

https://lists.apache.org/thread.html/r1125f3044a0946d1e7e6f125a6170b58d413ebd4a95157e4608041c7@%3Cannounce.apache.org%3E

lists.apache.org/thread.html/r0b000d... WEB

https://lists.apache.org/thread.html/r0b000dc028616d33cb9aa388eb45d516b789cab0024dad94bc06588a@%3Cissues.flink.apache.org%3E

Flink runtime Security Information SECURITY

http://www.openwall.com/lists/oss-security/2021/01/05/1

Frequently Asked Questions

What is CVE-2020-17518?

CVE-2020-17518 is a security vulnerability in Flink runtime involving Upload of file to arbitrary path in Apache Flink under CWE-23: Relative Path Traversal.

Which Flink runtime versions are affected?

Affected versions include releases prior to 1.11.3 across affected packages: org.apache.flink:flink-runtime.

What version fixes CVE-2020-17518?

Upgrading to 1.11.3 (or the latest patched release for your respective branch) resolves the vulnerability.

Is flink-runtime affected?

Yes, org.apache.flink:flink-runtime is affected in releases prior to 1.11.3. Upgrade your dependency to 1.11.3 or later.

What is the CVSS score of CVE-2020-17518?

CVE-2020-17518 has a CVSS v3.1 base score of 7.5 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.

What CWE is associated with CVE-2020-17518?

CVE-2020-17518 is classified under CWE-23: Relative Path Traversal (The product uses external input to construct a pathname that should be within a restricted directory, but it does not properly neutralize sequences such as ".." that can resolve to a location that is outside of that directory.).

How can I check Maven dependencies for CVE-2020-17518?

Run the dependency tree command: 'mvn dependency:tree -Dincludes=org.apache.flink'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.

Machine-readable OSV JSON OSV v1.5 Schema

Normalized schema output

View Raw JSON

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-7q5g-gph2-4rc6",
  "modified" : "2021-04-07T18:02:24Z",
  "published" : "2022-02-09T22:29:52Z",
  "aliases" : [ "CVE-2020-17518" ],
  "summary" : "Upload of file to arbitrary path in Apache Flink",
  "details" : "Apache Flink 1.5.1 introduced a REST handler that allows you to write an uploaded file to an arbitrary location on the local file system, through a maliciously modified HTTP HEADER. The files can be written to any location accessible by Flink 1.5.1. 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 a5264a6f41524afe8ceadf1d8ddc8c80f323ebc4 from apache/flink:master.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.apache.flink:flink-runtime"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "1.5.1"
      }, {
        "fixed" : "1.11.3"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2020-17518"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/apache/flink/commit/a5264a6f41524afe8ceadf1d8ddc8c80f323ebc4"
  }, {
    "type" : "WEB",
    "url" : "https://lists.apache.org/thread.html/rfe159ccf496d75813f24c6079c5d33872d83f5a2e39cb32c3aef5a73@%3Cissues.flink.apache.org%3E"
  }, {
    "type" : "WEB",
    "url" : "https://lists.apache.org/thread.html/rf8812a5703f4a5f1341138baf239258b250875699732cfdf9d55b21d@%3Cissues.flink.apache.org%3E"
  }, {
    "type" : "WEB",
    "url" : "https://lists.apache.org/thread.html/rec0d650fbd4ea1a5e1224a347d83a63cb44291c334ad58b8809bc23b@%3Cissues.flink.apache.org%3E"
  }, {
    "type" : "WEB",
    "url" : "https://lists.apache.org/thread.html/rd6a1a0e2d73220a65a8f6535bbcd24bb66adb0d046c4a1aa18777cf3@%3Cdev.flink.apache.org%3E"
  }, {
    "type" : "WEB",
    "url" : "https://lists.apache.org/thread.html/rd2467344f88bcaf108b8209ca92da8ec393c68174bfb8c27d1e20faa@%3Cdev.flink.apache.org%3E"
  }, {
    "type" : "WEB",
    "url" : "https://lists.apache.org/thread.html/rcb9e8af775f2a3706b69153aefde78f208871649df057c70ce2e24f9@%3Cissues.flink.apache.org%3E"
  }, {
    "type" : "WEB",
    "url" : "https://lists.apache.org/thread.html/rb43cd476419a48be89c1339b527a18116f23eec5b6df2b2acbfef261@%3Cuser.flink.apache.org%3E"
  }, {
    "type" : "WEB",
    "url" : "https://lists.apache.org/thread.html/rb43cd476419a48be89c1339b527a18116f23eec5b6df2b2acbfef261@%3Cdev.flink.apache.org%3E"
  }, {
    "type" : "WEB",
    "url" : "https://lists.apache.org/thread.html/rb43cd476419a48be89c1339b527a18116f23eec5b6df2b2acbfef261@%3Cannounce.apache.org%3E"
  }, {
    "type" : "WEB",
    "url" : "https://lists.apache.org/thread.html/rb43cd476419a48be89c1339b527a18116f23eec5b6df2b2acbfef261%40%3Cdev.flink.apache.org%3E"
  }, {
    "type" : "WEB",
    "url" : "https://lists.apache.org/thread.html/ra8c96bf3ccb4e491f9ce87ba35f134b4449beb2a38d1ce28fd89001f@%3Cdev.flink.apache.org%3E"
  }, {
    "type" : "WEB",
    "url" : "https://lists.apache.org/thread.html/r90890afea72a9571d666820b2fe5942a0a5f86be406fa31da3dd0922@%3Cannounce.apache.org%3E"
  }, {
    "type" : "WEB",
    "url" : "https://lists.apache.org/thread.html/r88200d2f0b620c6b4b1585a7171355005c89e678b01d0e71a16c57e7@%3Cissues.flink.apache.org%3E"
  }, {
    "type" : "WEB",
    "url" : "https://lists.apache.org/thread.html/r8167f30c4c60a11b8d5be3f55537beeda629be61196e693bde403b36@%3Cissues.flink.apache.org%3E"
  }, {
    "type" : "WEB",
    "url" : "https://lists.apache.org/thread.html/r7b2ee88c66fc1d0823e66475631f5c3e7f0365204ff0cb094d9f2433@%3Cissues.flink.apache.org%3E"
  }, {
    "type" : "WEB",
    "url" : "https://lists.apache.org/thread.html/r710693b0d3b229c81f485804ea1145b4edda79c9e77d66c39a0a2ff1@%3Cissues.flink.apache.org%3E"
  }, {
    "type" : "WEB",
    "url" : "https://lists.apache.org/thread.html/r705fb2211b82c9f1f8d2b1d4c823bcbca50402ba09b96608ec657efe@%3Cissues.flink.apache.org%3E"
  }, {
    "type" : "WEB",
    "url" : "https://lists.apache.org/thread.html/r5444acac3407ef6397d6aef1b5aec2db53b4b88ef221e63084c1e5f2@%3Cissues.flink.apache.org%3E"
  }, {
    "type" : "WEB",
    "url" : "https://lists.apache.org/thread.html/r4a87837518804b31eb9db3048347ed2bb7b46fbaad5844f22a9fd4dc@%3Cissues.flink.apache.org%3E"
  }, {
    "type" : "WEB",
    "url" : "https://lists.apache.org/thread.html/r28f17e564950d663e68cc6fe75756012dda62ac623766bb9bc5e7034@%3Cissues.flink.apache.org%3E"
  }, {
    "type" : "WEB",
    "url" : "https://lists.apache.org/thread.html/r26fcdd4fe288323006253437ebc4dd6fdfadfb5e93465a0e4f68420d@%3Cuser-zh.flink.apache.org%3E"
  }, {
    "type" : "WEB",
    "url" : "https://lists.apache.org/thread.html/r229167538863518738e02f4c1c5a8bb34c1d45dadcc97adf6676b0c1@%3Cdev.flink.apache.org%3E"
  }, {
    "type" : "WEB",
    "url" : "https://lists.apache.org/thread.html/r1125f3044a0946d1e7e6f125a6170b58d413ebd4a95157e4608041c7@%3Cannounce.apache.org%3E"
  }, {
    "type" : "WEB",
    "url" : "https://lists.apache.org/thread.html/r0b000dc028616d33cb9aa388eb45d516b789cab0024dad94bc06588a@%3Cissues.flink.apache.org%3E"
  }, {
    "type" : "WEB",
    "url" : "http://www.openwall.com/lists/oss-security/2021/01/05/1"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-22", "CWE-23" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-04-07T18:02:24Z",
    "nvd_published_at" : "2021-01-05T12:15:00Z"
  }
}

CVSS V3

7.5 HIGH

Attack Vector Network (AV:N)

Attack Complexity Low (AC:L)

Privileges Required None (PR:N)

User Interaction None (UI:N)

Scope Unchanged (S:U)

Confidentiality None (C:N)

Integrity High (I:H)

Availability None (A:N)

Vector String

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

Advisory Metadata

Source ID: GHSA-7q5g-gph2-4rc6
Schema Version: 1.4.0
Published: 2022-02-09 22:29
Last Modified: 2021-04-07 18:02
Database Record File: advisories/github-reviewed/2022/02/GHSA-7q5g-gph2-4rc6/GHSA-7q5g-gph2-4rc6.json