CVE-2026-68581 Vikunja 0.22.0 through 2.3.0 Authentication Bypass via Principal ID Collision
An attacker can bypass authentication in Vikunja by exploiting ID collisions to manage other users' API tokens, leading to privilege escalation and account takeover.
- 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-2026-68581?
CVE-2026-68581 is a high-severity authentication bypass vulnerability in go-vikunja vikunja, published on 2 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Vikunja versions 0.22.0 through 2.3.0 fail to validate the principal type in API token management. Because user IDs and link-share IDs are independent numeric sequences and both resolve through a generic web.Auth.GetID() interface, a link-share JWT whose numeric ID equals a target user's ID is treated as that user by the /api/v1/tokens endpoints. An authenticated attacker can obtain a target's numeric user ID via authenticated user search, then create link shares on an attacker-writable project until the link-share sequence reaches that value, and use the resulting link-share JWT to list, create, and delete the target user's API tokens (including issuing a new token with attacker-chosen scopes under the target's permissions). Fixed in version 2.4.0.
Weakness: CWE-863
Which versions are affected by CVE-2026-68581?
3 open source packages ship an affected version, including code.vikunja.io/api.
| Package | Affected | Fixed in |
|---|---|---|
code.vikunja.io/api Go | From 0.22.0 | None |
code.vikunja.io/api Go | From 0.22.0 | 2.4.0 |
code.vikunja.io/api Go | From 0.22.0 | 2.4.0 |
How do I fix CVE-2026-68581?
Upgrade code.vikunja.io/api to 2.4.0 or later.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-68581 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-68581 exists.
Sources
Also known as GHSA-vvcv-vpph-h844, GO-2026-6753.