---
id: "GHSA-g38j-7v97-x298"
kind: "vulnerability"
aliases: ["GHSA-g38j-7v97-x298", "GO-2026-6732"]
title: "Vikunja: CalDAV relation creation bypasses TaskRelation.CanCreate, allowing an unauthorized write into any task by known UID in code.vikunja.io/api"
severity: "medium"
cvss: null
epss: null
exploited: false
status: "open"
category: "package"
products: [{"name": "code.vikunja.io/api", "fixed": [], "affected": "all versions", "ecosystem": "go"}]
ecosystems: ["go"]
tags: ["caldav", "go", "package", "self-hosted", "vikunja"]
not_affected_if: ["caldav-disabled", "versions-at-or-above-v2.6.0"]
published_at: "2026-10-19T21:08:26+00:00"
first_seen_at: "2026-10-23T19:13:08+00:00"
updated_at: "2026-10-23T20:15:28+00:00"
sources: [{"source": "govuln", "url": "https://pkg.go.dev/vuln/GO-2026-6732", "first_seen_at": "2026-10-23T19:13:08+00:00"}]
---

# Vikunja: CalDAV relation creation bypasses TaskRelation.CanCreate, allowing an unauthorized write into any task by known UID in code.vikunja.io/api

Vikunja's CalDAV endpoint lets a user create task relations without the permission check that normally guards that action. An authenticated user who knows the UID of a task they cannot access can write a relation into that task.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- go:code.vikunja.io/api affected all versions fixed ?

## How to check

Check the Go module version of code.vikunja.io/api in go.mod, e.g. grep 'code.vikunja.io/api' go.mod
If the Vikunja server is run from a binary or container, check its version with the release tag used to build it

## Fix

Upgrade code.vikunja.io/api to v2.6.0 or later.

## Timeline

- 2026-10-23T19:13:08+00:00 govuln https://pkg.go.dev/vuln/GO-2026-6732

## From the sources

Vikunja: CalDAV relation creation bypasses TaskRelation.CanCreate, allowing an unauthorized write into any task by known UID in code.vikunja.io/api.

NOTE: The source advisory for this report contains additional versions that could not be automatically mapped to standard Go module versions.

(If this is causing false-positive reports from vulnerability scanners, please suggest an edit to the report.)

The additional affected modules and versions are: code.vikunja.io/api before v2.6.0.

---

_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_