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4.3Medium

CVE-2026-55064

Vikunja is an open-source self-hosted task management platform. From 2.3.0 until 2.4.0, a user with Write but not Admin permission on a shared child project can detach it from its parent hierarchy by submitting parent_project_id equal to 0 to POST /api/v1/projects/{project}. The Project.CanUpdate authorization check in pkg/models/project_permissions.go and UpdateProject logic in pkg/models/project.go only gate nonzero parent values, while UpdateProject always persists parent_project_id, so the explicit zero value bypasses the Admin requirement introduced for CVE-2026-35595. Detachment severs the recursive permission-inheritance chain and can disrupt the owner’s hierarchy and inherited collaborator access. This issue is fixed in version 2.4.0.

What this means for your business

  • An attacker can use it remotely, over a network, with an ordinary user login, and without anyone at your company clicking anything.
  • FIRST's prediction model gives it a 0.3% chance of attack attempts being seen in the next 30 days, ranking above 19% of all known flaws.

What to do

  1. 1Ask your IT team or provider whether any of your systems use the affected product.
  2. 2If you do, follow the vendor's guidance. No patch reference has been published yet.

Not sure if your company is exposed?

Fastnexa’s certified penetration testers can check whether attackers could use this flaw, or others like it, against your websites, apps and network. The full test is free for our first 10 founding clients until 31 December 2026.

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Scoring

CVSS
4.3 (v3.1)
Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
Weakness
CWE-862
Assigned by
security-advisories@github.com

Dates

Published
2026-08-28
Last modified
2026-09-09
Sources
NVD

References