CVE-2026-35599: Vikunja has an Algorithmic Complexity DoS in Repeating Task Handler

Vulnerability summary

CVE-2026-35599 is a medium (CVSS 6.5) Inefficient Algorithmic Complexity vulnerability in go-vikunja vikunja. EPSS estimates a 0.58% chance of exploitation in the next 30 days, higher than 47.1% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 10-04-2026
   PublishedVulnerability first disclosed.
2. 10-04-2026
   Last modifiedVulnerability information updated.

Description

Vikunja is an open-source self-hosted task management platform. Prior to 2.3.0, the addRepeatIntervalToTime function uses an O(n) loop that advances a date by the task's RepeatAfter duration until it exceeds the current time. By creating a repeating task with a 1-second interval and a due date far in the past, an attacker triggers billions of loop iterations, consuming CPU and holding a database connection for minutes per request. This vulnerability is fixed in 2.3.0.

• CWE-407Inefficient Algorithmic ComplexityAn algorithm in a product has an inefficient worst-case computational complexity that may be detrimental to system performance and can be triggered by an attacker, typically using crafted manipulations that ensure that the worst case is being reached.