CVE-2026-55066

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

Published: Aug 28, 2026Updated: Sep 9, 2026 Sources: CVE List NVDCWE-639

7.1HIGH

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.

No summary for this CVE yet.

CVSS Vector Breakdown

Exploitability

AV:NAttack Vector

Network

AC:LAttack Complexity

Low

PR:LPrivileges Required

Low

UI:NUser Interaction

None

Scope

S:UScope

Unchanged

Impact

C:HConfidentiality

High

I:LIntegrity

Low

A:NAvailability

None

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Weaknesses

CWE-639

Affected Products

go-vikunja

oss-projectaka vikunja

vikunjaOn-prem

Cloud & SaaS / saas-application

Exploitability

No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.

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Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

1 technique

Initial Access

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References

https://github.com/go-vikunja/vikunja/security/advisories/GHSA-5pg6-m483-7vrg

github.com

https://github.com/go-vikunja/vikunja/pull/3239

github.com

https://github.com/go-vikunja/vikunja/commit/36cdc2ce2be0b8ccc74227d178b92047d59cd65f

github.com

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