In Reactor Netty HTTP Server, versions 1.1.x prior to 1.1.13 and versions 1.0.x prior to 1.0.39, a malicious user can send a request using a specially crafted URL that can lead to a directory traversal attack.

Specifically, an application is vulnerable if Reactor Netty HTTP Server is configured to serve static resources.

• Reactor Netty
  • 1.1.0 to 1.1.12
  • 1.0.0 to 1.0.38
  • And older unsupported versions

Users of affected versions should apply the following mitigation. 1.1.x users should upgrade to 1.1.13. 1.0.x users should upgrade to 1.0.39. No other steps are necessary. Releases that have fixed this issue include:

• Reactor Netty
  • 1.1.13
  • 1.0.39

The issue was identified and responsibly reported by Dr. Michael Ummels from BVU Beratergruppe Verkehr + Umwelt GmbH