Emoji Input Validation Failure Enables Sidebar Layout Abuse
CVE-2026-77166 Published on September 21, 2026
The emoji field in the page emoji update endpoint does not properly validate user input. By injecting long text and line breaks, the sidebar layout becomes broken and can hide other items.
Weakness Type
Business Logic Errors
Weaknesses in this category identify some of the underlying problems that commonly allow attackers to manipulate the business logic of an application. Errors in business logic can be devastating to an entire application. They can be difficult to find automatically, since they typically involve legitimate use of the application's functionality. However, many business logic errors can exhibit patterns that are similar to well-understood implementation and design weaknesses.
Affected Versions
Nextcloud Collectives:- Version 3.2.1, <= 3.5.0 is affected.