# CVE-2026-123526: Vikunja before 2.7.1 Mass Assignment via Team external_id Field


- **Severity:** Medium 5.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Fix available:** No
- **Published:** 8 Nov 2026
- **Updated:** 9 Nov 2026
- **Also known as:** GHSA-cg54-92gp-5457, GHSA-fjrf-gjmg-9v6g

## What is CVE-2026-123526?

CVE-2026-123526 is a medium-severity vulnerability in go-vikunja vikunja, published on 8 Nov 2026. 

### Official description

Vikunja before 2.7.1 contains a mass assignment vulnerability that allows any authenticated user to set the read-only external_id field through the team create and update endpoints. Attackers can tag a team they create or administer as externally managed, permanently blocking removal of every member and causing SSO members to be dropped from the team at their next login.

Weakness: CWE-915 (Improperly Controlled Modification of Dynamically-Determined Object Attributes)

## Which versions are affected by CVE-2026-123526?


## How do I fix CVE-2026-123526?

No fix has been published for CVE-2026-123526 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-123526 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-123526 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-123526 and fix it if it is affected.

What it is: CVE-2026-123526 is a medium-severity vulnerability in go-vikunja vikunja, published on 8 Nov 2026. 
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-123526 exists.

Affected product: go-vikunja vikunja. 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-2026-123526/ (Markdown: https://insights.sbomify.com/CVE-2026-123526/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-123526
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-123526
- OSV: https://osv.dev/vulnerability/CVE-2026-123526

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-123526/
Summaries are generated and may contain mistakes; the official description above is the record.