CVE-2026-35599 Vikunja has an Algorithmic Complexity DoS in Repeating Task Handler
An attacker can cause a denial of service in Vikunja by creating repeating tasks with specific intervals that trigger excessive CPU usage and database connection holds.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-35599?
CVE-2026-35599 is a medium-severity denial of service vulnerability in go-vikunja vikunja, published on 10 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official 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.
Weakness: CWE-407
Which versions are affected by CVE-2026-35599?
3 open source packages ship an affected version, including code.vikunja.io/api. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
code.vikunja.io/api Go | All versions | None |
code.vikunja.io/api Go | All versions | 2.3.0 |
code.vikunja.io/api Go | All versions | 2.3.0 |
Products include Vikunja Vikunja.
How do I fix CVE-2026-35599?
Upgrade code.vikunja.io/api to 2.3.0 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-35599 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-35599 exists.
Other vulnerabilities in go-vikunja vikunja
- CVE-2026-28268 Vikunja Vulnerable to Account Takeover via Password Reset Token Reuse
- CVE-2026-27575 Vijkunja has Weak Password Policy Combined with Persistent Sessions After Password Change
- CVE-2026-25935 Vikunja Affected by XSS Via Task Preview
- CVE-2026-35595 Vikunja Affected by Privilege Escalation via Project Reparenting
- CVE-2026-33316 Vikunja’s Improper Access Control Enables Bypass of Administrator-Imposed Account Disablement
Sources
Also known as GHSA-r4fg-73rc-hhh7, GO-2026-5608.