Vikunja: Cross-tenant task-position rows can be injected into arbitrary project views via the unvalidated project_view_id in the task position endpoint (v1 and v2) — GHSA-W39F-H553-H2MX

Summary

## Summary The task-position endpoint authorizes only the task side of the write: `TaskPosition.CanUpdate` delegates to `Task.CanUpdate` (write access to the task's own project) and the request body's `project_view_id` is never validated to belong to the task's project, nor is any access to that view required. Any authenticated user with a single writable task of their own can persist `(task_id, project_view_id,…

Timeline

Published by source

2026-10-09

Risk context

• Reported severity or threat level: medium.
• Reported CVSS score: 5.3 out of 10.
• Reported EPSS value: 0.00264.
• Review exposure for the affected product or family: go: code.vikunja.io/api.

Product

go: code.vikunja.io/api

What to do

General, cautious steps (verify details in the official source):

• Review exposure and plan remediation based on risk and environment.
• Identify affected product versions in your inventory and verify whether you are impacted.
• Apply vendor patches/updates or recommended mitigations as soon as available.
• Read the official advisory for exact affected versions and remediation steps.

Official advisory

• Read the official source
• CVE Record
• NVD

Evidence and provenance

Canonical advisory ID

GHSA-W39F-H553-H2MX

Source

GitHub

Vendor

GitHub

Published by source

2026-10-09

Last source activity

2026-10-09

Additional identifiers

CVE-2026-91984

Curated by

hlukh.ch

Related advisories and connections

These advisories are connected by shared CVE, product, vendor, source, or time signals.