In affected versions of Octopus Server, an authenticated user with permissions to edit an Environment or Project can set specifically crafted JSON content for the object. Insecure deserialization of this content allows the user to execute a…

{
                    "vendor": "Octopus Deploy",
                    "product": "Octopus Server",
                    "platforms": [
                        "Windows",
                        "Linux"
                    ],
                    "versions": [
                        {
                            "status": "affected",
                            "version": "2019.4.1",
                            "lessThan": "2026.1.11781",
                            "versionType": "custom"
                        },
                        {
                            "status": "affected",
                            "version": "2026.2.0",
                            "lessThan": "2026.2.13441",
                            "versionType": "custom"
                        },
                        {
                            "status": "affected",
                            "version": "2026.3.0",
                            "lessThan": "2026.3.15829",
                            "versionType": "custom"
                        }
                    ],
                    "defaultStatus": "unaffected"
                }