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GHSA-9xwc-vwww-qqmw

Duplicate Advisory: Vikunja: Link-share principal-type confusion enables cross-account team removal, bot takeover, and roster disclosure

High Withdrawn Oct 9, 2026 Go
Severity
0.0 / 10
High · CVSS 4.0
Exploit chance (EPSS)
—
No score published
Known exploited
No
Not in CISA's catalog
Weakness
CWE-639 Authorization Bypass Through User-Controlled Key
Fix
None yet
No fixed version published

Description

Duplicate Advisory

This advisory has been withdrawn because it is a duplicate of GHSA-32r8-5843-4qw2. This link is maintained to preserve external references.

Original Description

Vikunja through 2.4.0 contains a principal-type confusion vulnerability where LinkSharing principals with id N are treated as user principals with users.id == N at three permission checks lacking type guards. Attackers with a link-share JWT can remove victims from teams, enumerate and delete victim bot users, or read team rosters by exploiting id collisions in the autoincrement space.

Affected versions

Go

PackageVulnerableFixed in
code.vikunja.io/api
<= 2.4.0
No fix yet

How to fix

No fixed version has been published yet. Until one is, remove or replace the package, or turn off or isolate the affected feature. This page updates when a fix ships.

Severity breakdown

CVSS 4.0 0.0

CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Attack vector
Network
Attack complexity
High
Attack requirements
Present
Privileges required
Low
User interaction
None
Confidentiality (vulnerable system)
High
Integrity (vulnerable system)
High
Availability (vulnerable system)
High
Confidentiality (subsequent systems)
None
Integrity (subsequent systems)
None
Availability (subsequent systems)
None
Exploit maturity
Not defined
Scope
X

CVSS 3.1 7.5

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

Attack vector
Network
Attack complexity
High
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Weakness

CWE-639: Authorization Bypass Through User-Controlled Key

The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.

How to prevent it
  • Architecture and Design: For each and every data access, ensure that the user has sufficient privilege to access the record that is being requested.
  • Architecture and Design, Implementation: Make sure that the key that is used in the lookup of a specific user's record is not controllable externally by the user or that any tampering can be detected.
  • Architecture and Design: Use encryption in order to make it more difficult to guess other legitimate values of the key or associate a digital signature with the key so that the server can verify that there has been no tampering.

References

Timeline

  1. Published
  2. Withdrawn
  3. Last updated by the source
AdvisorySeverityWhy it's related
GHSA-m687-p538-r5hp
Vikunja: Permissive Cross-domain Security Policy trusts every localhost origin which should not be trusted
Medium Also affects code.vikunja.io/api
GHSA-fmmf-xq98-g327
Vikunja: Write-level project members can delete admin-tier link shares through an unloaded permission check
Medium Also affects code.vikunja.io/api
GHSA-pjr3-86v4-5p7w
Vikunja: Explicit lower-permission share on a sub-project is silently overridden by an inherited parent permission (broken access control / privilege-management regression in v2.6.0)
Medium Also affects code.vikunja.io/api
GHSA-hjx8-qv73-f7cm
Vikunja: Webhooks and link shares survive every revocation path, so a removed collaborator keeps a live feed
High Also affects code.vikunja.io/api
GHSA-fprf-r6rv-xg99
Vikunja: Saved filter creation with an empty filter string recalculates task positions across all tenants
Medium Also affects code.vikunja.io/api
GHSA-4hv6-xc92-j86g
Vikunja: WebSocket authentication ignores server-side session state, so revoked sessions keep receiving live pushes
High Also affects code.vikunja.io/api
GHSA-w2ch-4xgr-22ww
Vikunja: Task relation deletion does not check read access to the other task, allowing cross-project relation removal
Low Also affects code.vikunja.io/api
GHSA-8wvg-r2j4-3737
Vikunja: Assignee email addresses disclosed to read-only project members via the task assignees endpoint
Medium Also affects code.vikunja.io/api
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