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

[Robert Metzger <rmetzger () apache org>]

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

Vendor:
The Apache Software Foundation

Versions Affected:
1.5.1 to 1.11.2

Description:
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.

Mitigation:
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.

Credits:
This issue was discovered by 0rich1 of Ant Security FG Lab