# CVE-2026-91984

## Summary

- **CVE ID:** CVE-2026-91984
- **Severity:** MEDIUM
- **CVSS Score:** 5.3 (CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N)
- **CWE:** CWE-639
- **Published:** Sep 15, 2026
- **Last Modified:** Sep 15, 2026

## Description

Vikunja before 2.6.0 fails to validate that user-supplied project_view_id in task-position requests belongs to the task's project. Authenticated attackers can insert task position rows into arbitrary other tenant project views via POST or PUT task-position endpoints.

## Affected Products

- go-vikunja — vikunja (0)
- go-vikunja — vikunja (2.6.0)

## References

- [CNA](https://github.com/go-vikunja/vikunja/security/advisories/GHSA-w39f-h553-h2mx)
- [CNA](https://www.vulncheck.com/advisories/vikunja-before-2.6.0-broken-object-level-authorization-via-task-position)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.21%
- **EPSS Percentile:** 11.1

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-17._