What’s Vulnerable › Vulnerabilities

CVE-2026-55066: Vikunja: Cross-tenant IDOR in kanban move-task endpoint via unauthorized body task_id

• Severity: high (CVSS 7.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-28 · updated 2026-09-09
• Weakness: CWE-639

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.

Affected products

• go-vikunja vikunja: before 2.4.0

References

• https://github.com/go-vikunja/vikunja/commit/36cdc2ce2be0b8ccc74227d178b92047d59cd65f
• https://github.com/go-vikunja/vikunja/pull/3239
• https://github.com/go-vikunja/vikunja/releases/tag/v2.4.0
• https://github.com/go-vikunja/vikunja/security/advisories/GHSA-5pg6-m483-7vrg

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