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Vulnerability · Published Jan 5, 2021 · Assigned by apache

CVE-2020-17518Apache Flink directory traversal attack: remote file writing through the REST API

High 7.5

In plain English

A high-severity security flaw in Apache Flink from Apache Software Foundation. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 49.1% (higher than 99% of all known vulnerabilities). Ready-made attack tooling exists: Nuclei, public proof-of-concept code. Fixed versions are available - upgrade the affected package.

Severity (CVSS NVD)7.5High
Exploit odds (30 days)49.1%top 1.1% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack tooling2Nuclei, Public PoC

Official description

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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Mavenorg.apache.flink:flink-runtime1.11.3GHSA-7q5g-gph2-4rc6

Affected products (as reported)

VendorProductVersions
Apache Software Foundation Apache Flink Apache Flink 1.5.1 to 1.11.2

Weakness: CWE-23

References