# CVE-2026-30843: Wekan has Cross-Board IDOR in Custom Fields Update Endpoints


- **Severity:** Critical 9.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N`)
- **Exploited in the wild:** Not known
- **Fix available:** No
- **Published:** 6 Mar 2026
- **Updated:** 9 Mar 2026

## What is CVE-2026-30843?

CVE-2026-30843 is a critical vulnerability in Wekan, published on 6 Mar 2026. 

### Official description

Wekan is an open source kanban tool built with Meteor. Versions 8.32 and 8.33 have a critical Insecure Direct Object Reference (IDOR) issue which could allow unauthorized users to modify custom fields across boards through its custom fields update endpoints, potentially leading to unauthorized data manipulation. The PUT /api/boards/:boardId/custom-fields/:customFieldId endpoint in Wekan validates that the authenticated user has access to the specified boardId, but the subsequent database update uses only the custom field's _id as a filter without confirming the field actually belongs to that board. This means an attacker who owns any board can modify custom fields on any other board by supplying a foreign custom field ID, and the same flaw exists in the POST, PUT, and DELETE endpoints for dropdown items under custom fields. The required custom field IDs can be obtained by exporting a board (which only needs read access), since the exported JSON includes the IDs of all board components. The authorization check is performed against the wrong resource, allowing cross-board custom field manipulation. This issue has been fixed in version 8.34.

Weakness: CWE-639 (Authorization Bypass Through User-Controlled Key)

## Which versions are affected by CVE-2026-30843?

It affects 1 product.


Products: Wekan Project Wekan.

## How do I fix CVE-2026-30843?

No fix has been published for CVE-2026-30843 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-30843 being exploited?

There is no known exploitation of CVE-2026-30843 in the wild and no public exploit code.

## Other vulnerabilities in Wekan

- [CVE-2026-30844](https://insights.sbomify.com/CVE-2026-30844/): Wekan Vulnerable to SSRF through Lack of Validation or Filtering in Attachment URL Loading (critical 9.3)
- [CVE-2026-30847](https://insights.sbomify.com/CVE-2026-30847/): Wekan Credential Leak via notificationUsers Publication Exposes Password Hashes and Session Tokens (critical 9.3)
- [CVE-2025-65780](https://insights.sbomify.com/CVE-2025-65780/): Missing authorization in n/a (high 8.8)
- [CVE-2026-30846](https://insights.sbomify.com/CVE-2026-30846/): Wekan Exposes All Global Webhook Integrations through globalwebhooks Publication (high 8.7)
- [CVE-2026-25560](https://insights.sbomify.com/CVE-2026-25560/): WeKan < 8.19 LDAP Authentication Filter Injection (high 8.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-30843 and fix it if it is affected.

What it is: CVE-2026-30843 is a critical vulnerability in Wekan, published on 6 Mar 2026. 
Exploitation: There is no known exploitation of CVE-2026-30843 in the wild and no public exploit code.

Affected product: Wekan. No package-level version data is available, so check the vendor advisory linked from the reference page.

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-2026-30843/ (Markdown: https://insights.sbomify.com/CVE-2026-30843/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-30843
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-30843
- OSV: https://osv.dev/vulnerability/CVE-2026-30843

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-30843/
Summaries are generated and may contain mistakes; the official description above is the record.