Knowledge base permissions allow you to configure the visibility and actions on articles and KB sections.
There are two permissions under Manage >> Roles & Permissions >> Managerial related to Knowledge Base:
Manage Knowledge Base Sections and Articles:
With this permission enabled, New articles and sections can be created. Besides, Editing and Deleting articles are allowed.
With the above permission disabled, only View access to articles is allowed.
View KB sections & articles of unassociated categories:
Knowledgebase articles are grouped into sections. These sections can be associated with categories. When an agent (belonging to a role) has this permission enabled, he can access all articles and sections irrespective of whether he has access to the categories the section is associated with.
While it is disabled, the agent cannot view or create articles under sections that belong to categories he doesn't have access to.