---
id: CVE-2026-76216
title: >-
  Vikunja through 2.4.0 contains a principal-type confusion vulnerability where
  LinkSharing principals with id N are treated as user principals with users.id
  == N at three permission checks lacking type guards
summary: >-
  Vikunja through 2.4.0 contains a principal-type confusion vulnerability where
  LinkSharing principals with id N are treated as user principals with users.id
  == N at three permission checks lacking type guards. Attackers with a
  link-share …
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-639
  - CWE-843
  - CWE-863
published: '2026-08-19'
updated: '2026-09-16'
sourceUpdated: '2026-09-16T20:18:30.540'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-76216'
references:
  - url: >-
      https://github.com/go-vikunja/vikunja/security/advisories/GHSA-32r8-5843-4qw2
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/vikunja-through-principal-type-confusion-via-linksharing
    label: disclosure@vulncheck.com
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-76216'
  - url: 'https://github.com/advisories/GHSA-32r8-5843-4qw2'
  - url: 'https://github.com/go-vikunja/vikunja'
  - url: >-
      https://github.com/go-vikunja/vikunja/commit/a717d64d5658708ba390f18dd697f5e567e68aac
  - url: 'https://github.com/go-vikunja/vikunja/releases/tag/v2.5.0'
tags:
  - nvd
  - ghsa
  - go
  - osv
epss: 0.00363
epssPercentile: 0.29924
ingestedAt: '2026-09-16T21:05:36.839Z'
aliases:
  - GHSA-32r8-5843-4qw2
  - GO-2026-6711
ecosystem: go
vendor: api
product: code.vikunja.io/api
affected:
  - code.vikunja.io/api <= 2.4.0
patched:
  - code.vikunja.io/api 2.5.0
---

## Overview

Vikunja through 2.4.0 contains a principal-type confusion vulnerability where LinkSharing principals with id N are treated as user principals with users.id == N at three permission checks lacking type guards. Attackers with a link-share JWT can remove victims from teams, enumerate and delete victim bot users, or read team rosters by exploiting id collisions in the autoincrement space.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2026-76216)

Affected packages:

- `code.vikunja.io/api <= 2.4.0`

Source: https://github.com/advisories/GHSA-32r8-5843-4qw2