PT-2026-31985 · Vikunja · Vikunja

Published 2026-04-10 · Updated 2026-04-10 · CVE-2026-40103

Positive Technologies (AI Summary)

CVSS v3.1

5.4

Medium

Base vector

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

Name of the Vulnerable Software and Affected Versions Vikunja versions prior to 2.3.0

Description Vikunja, a self-hosted task management platform, has a scoped API token enforcement issue for custom project background routes. A token with only projects.background permission can successfully delete a project background, while a token with only projects.background delete permission is rejected. This is a scoped-token authorization bypass. The issue affects the /api/v1/projects/:project/background endpoint, specifically the DELETE method. The CanDoAPIRoute() function incorrectly handles permission checks, falling back to the parent group and reconstructing the child permission from the path segments, allowing a token with projects.background to bypass the intended projects.background delete requirement for deleting project backgrounds. This could allow an attacker with a valid API token and projects.background permission to delete project backgrounds.

Recommendations Update to version 2.3.0 or later.

Fix

Incorrect Authorization

Weakness Enumeration

CWE-863

CWE-836

Related Identifiers

CVE-2026-40103

GHSA-V479-VF79-MG83

Affected Products

Vikunja

References · 8

• https://github.com/go-vikunja/vikunja/commit/6a0f39b252a81fa4b19dc56dc889183acc9225ae · Patch
• https://github.com/go-vikunja/vikunja/security/advisories/GHSA-v479-vf79-mg83 · Vendor Advisory
• https://osv.dev/vulnerability/GHSA-v479-vf79-mg83 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-40103 · Security Note
• https://github.com/go-vikunja/vikunja/releases/tag/v2.3.0 · Note
• https://github.com/go-vikunja/vikunja · Note
• https://github.com/go-vikunja/vikunja/pull/2584 · Note
• https://twitter.com/CVEnew/status/2042710233630277679 · Twitter Post