Jodit Editor is a WYSIWYG editor with written in pure TypeScript file and image editing capabilities. In versions prior to 4.12.18, Jodit.configure(options) — and the internal ConfigMerge / ConfigProto helpers — merged user-supplied options into the editor configuration without filtering prototype-mutating keys, potentially causing a Prototype Pollution vulnerability. A payload nested under an existing plain-object option such as controls could reach and mutate Object.prototype. Applications that pass user-controlled or partially user-controlled configuration into Jodit.configure() may be vulnerable. This issue was fixed in version 4.12.18.