CVE-2026-77166: nextcloud collectives Business Logic Errors

Vulnerability summary

CVE-2026-77166 is a low (CVSS 2.4) Business Logic Errors vulnerability in nextcloud collectives. EPSS estimates a 0.28% chance of exploitation in the next 30 days, higher than 19.7% of scored vulnerabilities.

Timeline

1. 21-09-2026
   PublishedVulnerability first disclosed.
2. 21-09-2026
   Last modifiedVulnerability information updated.

Description

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.

• CWE-840Business Logic ErrorsWeaknesses 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.