# 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.

- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 11 Sep 2026
- **Updated:** 15 Sep 2026
- **Also known as:** GHSA-6h3c-r723-7fx3

## 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 (Authorization Bypass Through User-Controlled Key)

## Which versions are affected by CVE-2026-49464?

2 open source packages ship an affected version, including nl.nl-portal:taak.


| Package | Ecosystem | 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.

## Is CVE-2026-49464 being exploited?

There is no known exploitation of CVE-2026-49464 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-49464 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-49464 in the wild and no public exploit code.

Affected packages and fixed versions:
- nl.nl-portal:taak (Maven): affected from 1.5.0; fixed in 3.0.1
- nl.nl-portal:taak (Maven): affected from 1.5.0; fixed in 3.0.1

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-49464/ (Markdown: https://insights.sbomify.com/CVE-2026-49464/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-49464
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-49464
- OSV: https://osv.dev/vulnerability/CVE-2026-49464

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-49464/
Summaries are generated and may contain mistakes; the official description above is the record.