Vikunja: Cross-tenant IDOR in kanban move-task endpoint via unauthorized body task_id (CVE-2026-55066) | HOL Guard CVE

High · CVSS 7.1CVE-2026-55066GHSA-5PG6-M483-7VRG

Vikunja: Cross-tenant IDOR in kanban move-task endpoint via unauthorized body task_id

Answer in brief

CVE-2026-55066 records a High severity (CVSS 7.1) vulnerability in Vikunja: Cross-tenant IDOR in kanban move-task endpoint via unauthorized body task_id. The current sources do not mark it as known exploited. The current feed maps go-vikunja/vikunja (generic), code.vikunja.io/api (go). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Aug 28, 2026Updated Aug 28, 2026Source checked Aug 28, 2026First seen by HOL Aug 28, 2026Material review Aug 28, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 7.1
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Available

Why this deserves its current priority

CVSS is 7.1. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps go-vikunja/vikunja (generic), code.vikunja.io/api (go). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
go-vikunja/vikunjageneric	< 2.4.0	Not reported
code.vikunja.io/apigo	<=2.3.0	2.4.0

Recommended response

Check inventory. Check lockfiles and deployed manifests for go-vikunja/vikunja, code.vikunja.io/api.
Review the reported fix. Update code.vikunja.io/api to 2.4.0 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Aug 28, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Aug 28, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 28, 2026

Sources and claim methodology

Upstream source description

Vikunja is an open-source self-hosted task management platform. Prior to 2.4.0, POST /api/v1/projects/{project}/views/{view}/buckets/{bucket}/tasks accepts a body supplied task_id but TaskBucket.CanUpdate in pkg/models/kanban_task_bucket.go authorizes only the project, view, and bucket from the URL. updateTaskBucket then calls Task.ReadOne without a separate task permission check, returns the victim task contents, and can update the task done state when the attacker chooses a done bucket. Because task identifiers are global sequential values, an authenticated user can enumerate cross-tenant tasks and modify their completion metadata through both the v1 and v2 routes that share this model. This issue is fixed in version 2.4.0.

Quoted source text, attributed separately from HOL analysis.