CVE-2026-49464 NL Portal: IDOR allows any authenticated user to complete and tamper with another user's taak
Authenticated users can read and modify other users' tasks due to missing ownership checks in the NL Portal backend library.
- 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-2026-49464?
CVE-2026-49464 is a high-severity missing authorization vulnerability in nl-portal-backend-libraries, published on 11 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
NL Portal Backend Libraries provide backend components for Dutch government portals that interact with residents, customers, suppliers, and partner organizations. The `nl.nl-portal:taak` package from version 1.5.0 through 3.0.0 fails to verify ownership when processing the `submitTaakV2` GraphQL mutation, allowing an authenticated user who knows or guesses another user’s task ID to read its form data, overwrite its submitted data, and mark the task as completed. Version 3.0.1 contains a patch. As a workaround, block the `submitTaakV2` mutation at the API gateway or restrict the `/graphql` endpoint to trusted networks
Weakness: CWE-639
Which versions are affected by CVE-2026-49464?
2 open source packages ship an affected version, including nl.nl-portal:taak.
| Package | Affected | Fixed in |
|---|---|---|
nl.nl-portal:taak Maven | From 1.5.0 | 3.0.1 |
nl.nl-portal:taak Maven | From 1.5.0 | 3.0.1 |
How do I fix CVE-2026-49464?
Upgrade nl.nl-portal:taak to 3.0.1 or later.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-49464 being exploited?
There is no known exploitation of CVE-2026-49464 in the wild and no public exploit code.
Sources
Also known as GHSA-6h3c-r723-7fx3.