CVE-2026-33312

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.

Reproduction

1. User A creates a project and sets a background image.
2. User A shares the project with User B with read-only permission.
3. User B sends: DELETE /api/v1/projects/{project_id}/background with a valid auth token.
4. 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.go line 665, route registration

Credits

This vulnerability was found using GitHub Security Lab Taskflows.

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.

The application does not correctly enforce access controls, allowing a principal to access resources or operations beyond their granted permissions. Typical impact: unauthorized data access or execution of privileged operations.

Kodem intelligence

1. What is CVE-2026-33312? CVE-2026-33312 is a medium-severity incorrect authorization vulnerability in code.vikunja.io/api (go), affecting versions >= 0.20.2, < 2.2.0. It is fixed in 2.2.0. The application does not correctly enforce access controls, allowing a principal to access resources or operations beyond their granted permissions.
2. Which versions of code.vikunja.io/api are affected by CVE-2026-33312? code.vikunja.io/api (go) versions >= 0.20.2, < 2.2.0 is affected.
3. Is there a fix for CVE-2026-33312? Yes. CVE-2026-33312 is fixed in 2.2.0. Upgrade to this version or later.
4. Is CVE-2026-33312 exploitable, and should I be worried? Whether CVE-2026-33312 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
5. What actually determines whether CVE-2026-33312 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
6. How do I fix CVE-2026-33312? Upgrade code.vikunja.io/api to 2.2.0 or later.

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