GHSA-564f-wx8x-878h CVE-2026-33312 GO-2026-4795
Vikunja read-only users can delete project background images via broken object-level authorization
- Severity
- 0.0 / 10
- Medium · CVSS 4.0
- Exploit chance (EPSS)
- 0.22%
- Chance of exploitation in the next 30 days. Higher than 12.48% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-863 Incorrect Authorization
- Fix
2.2.0- Upgrade code.vikunja.io/api to this version or later
Description
Summary
The DELETE /api/v1/projects/:project/background endpoint checks CanRead permission instead of CanUpdate, allowing any user with read-only access to a project to permanently delete its background image.
Details
The RemoveProjectBackground handler (pkg/modules/background/handler/background.go) reuses checkProjectBackgroundRights, a helper originally written for the read-only GetProjectBackground endpoint. This helper only verifies CanRead permission. In contrast, the handler for setting a background (setBackgroundPreparations) correctly checks CanUpdate.
As a result, destructive write operations (deleting the background file from storage and clearing the project's background_file_id and background_blur_hash fields) are gated behind a read-only permission check.
Impact
A user with read-only access to a project — via direct sharing, team membership, link share tokens with read permission, or read-scoped API tokens — can permanently delete the project's background image. The background file is removed from storage and cannot be recovered. This constitutes unauthorized data destruction.
Reproduction
- User A creates a project and sets a background image.
- User A shares the project with User B with read-only permission.
- User B sends:
DELETE /api/v1/projects/{project_id}/backgroundwith a valid auth token. - The request succeeds. The background image is permanently deleted.
References
pkg/modules/background/handler/background.go—RemoveProjectBackground(line 416),checkProjectBackgroundRights(line 304),setBackgroundPreparations(line 106)pkg/routes/routes.goline 665 — route registration
Credits
This vulnerability was found using GitHub Security Lab Taskflows.
Affected versions
Go
| Package | Vulnerable | Fixed in |
|---|---|---|
| code.vikunja.io/api | >= 0.20.2, < 2.2.0 |
2.2.0 |
| code.vikunja.io/api | >= 0.20.2 |
No fix yet |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
code.vikunja.io/api Go → 2.2.0
- go
go get code.vikunja.io/api@v2.2.0 && go mod tidy
Severity breakdown
CVSS 4.0 0.0
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
- Attack vector
- Network
- Attack complexity
- Low
- Attack requirements
- None
- Privileges required
- Low
- User interaction
- None
- Confidentiality (vulnerable system)
- None
- Integrity (vulnerable system)
- None
- Availability (vulnerable system)
- Low
- Confidentiality (subsequent systems)
- None
- Integrity (subsequent systems)
- None
- Availability (subsequent systems)
- None
CVSS 3.1 5.4
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- Low
- Availability
- Low
Weakness
CWE-863: Incorrect Authorization
The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.
How to prevent it
- Architecture and Design: Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) [REF-229] to enforce the roles at the appropriate boundaries. Note that this approach may not protect against horizontal authorization, i.e., it will not protect a user from attacking others with the same role.
- Architecture and Design: Ensure that access control checks are performed related to the business logic. These checks may be different than the access control checks that are applied to more generic resources such as files, connections, processes, memory, and database records. For example, a database may restrict access for medical records to a specific database user, but each record might only be intended to be accessible to the patient and the patient's doctor [REF-7].
- Architecture and Design: Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, consider using authorization frameworks such as the JAAS Authorization Framework [REF-233] and the OWASP ESAPI Access Control feature [REF-45].
- Architecture and Design: For web applications, make sure that the access control mechanism is enforced correctly at the server side on every page. Users should not be able to access any unauthorized functionality or information by simply requesting direct access to that page. One way to do this is to ensure that all pages containing sensitive information are not cached, and that all such pages restrict access to requests that are accompanied by an active and authenticated session token associated with a user who has the required permissions to access that page.
- System Configuration, Installation: Use the access control capabilities of your operating system and server environment and define your access control lists accordingly. Use a "default deny" policy when defining these ACLs.
References
Advisories
Packages
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why 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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