CVE-2026-91983 Vikunja before 2.6.0 API Token Scope Bypass via expand Parameter
Attackers with limited API tokens can bypass scope restrictions to read restricted task data like comments and time entries.
- 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-2026-91983?
CVE-2026-91983 is a medium-severity missing authorization vulnerability in go-vikunja vikunja, published on 15 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Vikunja before 2.6.0 contains an API token scope bypass vulnerability in task read endpoints where authorization fails to inspect query string parameters. Attackers with limited token scopes can use the expand parameter to access restricted data like comments, reactions, and time entries without proper permission verification.
Weakness: CWE-863
Which versions are affected by CVE-2026-91983?
3 open source packages ship an affected version, including code.vikunja.io/api.
| Package | Affected | Fixed in |
|---|---|---|
code.vikunja.io/api Go | All versions | None |
code.vikunja.io/api Go | From 1.0.0 | 2.6.0 |
code.vikunja.io/api Go | From 1.0.0 | 2.6.0 |
How do I fix CVE-2026-91983?
Upgrade code.vikunja.io/api to 2.6.0 or later.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-91983 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-91983 exists.
Sources
Also known as GHSA-9rg3-v78m-26q8, GO-2026-6726.