Apache Flink directory traversal attack: remote file writing through the REST API

Summary

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.

Timeline

1. Jan 5, 2021, 11:40 AM UTCCVE published
2. Feb 13, 2025, 4:27 PM UTCRecord last updated
3. Oct 28, 2026EPSS reached 10%

   FIRST estimates at least a 10% chance of exploitation in the next 30 days

Affected versions

• Apache Software Foundation Apache Flink

  Apache Flink 1.5.1 to 1.11.2

• org.apache.flink:flink-runtimeMaven

  From 1.5.1 · fixed in 1.11.3

References 28