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Fencer Vulns
medium 4.3

CVE-2026-55064 json

Vikunja incomplete fix for CVE-2026-35595: Write-only user can detach shared project from parent hierarchy via parent_project_id=0

published 2026-08-28 2 mo ago modified 2026-09-09 1 mo ago also EUVD-2026-67831 , GHSA-44v6-7fxq-vgf4 , GO-2026-6306

cvss
4.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 30%
public exploits
0
none known

Summary

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.

Patch / fix

  • go code.vikunja.io/api 2.4.0
  • vikunja vikunja 2.4.0
  • govulncheck-vulndb SLES 16.0, SLES for SAP applications 16.0 0.0.20260902T191204-160000.1.1

suse advisories SUSE-SU-2026:23692-1SUSE-SU-2026:23712-1

  • govulncheck-vulndb openSUSE Leap 16.0 0.0.20260902T191204-160000.1.1

opensuse advisories openSUSE-SU-2026:21812-1

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
2 mo ago

Exploit prediction

0.37% chance of exploitation in the next 30 days, higher than 30% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/go-vikunja/vikunja/security/advisories/GHSA-44v6-7fxq-vgf4 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
GitHub 3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

Affected packages

ecosystem package affected fixed in
go code.vikunja.io/api
>=2.3.0, <2.4.0
all versions
2.4.0

Affected products

  • go-vikunja vikunja

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.