CVE-2020-17518: Apache Flink

High severity, CVSS 7.5. EPSS: 51.4% chance of exploitation in the next 30 days.

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 products

• Apache Flink: from 1.5.1, before 1.11.3 (fixed in 1.11.3)

Published 2021-01-05. Last modified 2026-06-17.