Security Advisory 2024-02

Summary API key disclosed in Octopus Server audit log
Advisory Number 2024-02
Discovery Date 23 Jul 2023
Patch Release Date 27 Jul 2023
Advisory Release Date 17 Apr 2024
Product Octopus Server
Operating System Linux and Microsoft Windows
Severity Medium
CVE ID CVE-2023-4509

Customers who have downloaded and installed any of the Octopus Server versions listed below ("Details") are affected.

Please upgrade your Octopus Server immediately to fix this vulnerability.

Customers who have upgraded Octopus Server to version 2024.1.12401 or higher are not affected.


Octopus Deploy has given this vulnerability a Medium rating. This rating was given according to the Octopus Deploy severity levels, which ranks vulnerabilities as critical, high, medium, or low severity.

This is our assessment and you should evaluate its applicability to your own environment.


In affected versions of Octopus Deploy it is possible for an API key to be logged in clear text in the audit log file after an invalid login attempt.

The versions of Octopus Server affected by this vulnerability are:

  • All 2018.9.x, 2019.x.x, 2020.x.x, 2021.x.x, 2022.x.x versions
  • All 2023.1.x, 2023.2.x, 2023.3.x versions
  • All 2023.4.x versions before 2023.4.296
  • All 2024.2.x versions before 2024.2.101

As of 16/04/2024 Octopus Server version 2024.2.x is only available on Octopus Cloud.


To address this vulnerability, we have released Octopus Server versions that contain a fix for this issue:

  • 2023.4.296
  • 2024.1.437
  • 2024.2.101

The latest versions of Octopus Deploy products can be downloaded from and previous versions can be downloaded from

What You Need to Do

Octopus Deploy recommends that you upgrade to the latest version (2024.1.12401). You can download the latest version of Octopus Server from

If you can't upgrade to the latest version (2024.1.12401):

If you have feature version... ...then upgrade to this version
2018.9.x, 2019.x, 2020.x, 2021.x, 2022.x 2024.1.12401 or greater
2023.1.x, 2023.2.x, 2023.3.x 2024.1.12401 or greater
2023.4.x 2023.4.296 or greater
2024.1.x 2024.1.437 or greater


There is no known mitigation for CVE-2023-4509, it is important to upgrade to a fixed version as soon as possible.


If you have any questions or concerns regarding this advisory, please contact our support team

Exploitation and Public Announcements

The Octopus Deploy security team is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.


This vulnerability was found during internal testing by an Octopus Deploy engineer.