Vulnerability · Published Aug 2, 2026 · Assigned by VulnCheck

CVE-2026-68581Vikunja 0.22.0 through 2.3.0 Authentication Bypass via Principal ID Collision

High 8.1

In plain English

A high-severity incorrect authorization in vikunja from go-vikunja. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 40% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)8.1High

Exploit odds (30 days)0.5%top 59.6% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

Vikunja versions 0.22.0 through 2.3.0 fail to validate the principal type in API token management. Because user IDs and link-share IDs are independent numeric sequences and both resolve through a generic web.Auth.GetID() interface, a link-share JWT whose numeric ID equals a target user's ID is treated as that user by the /api/v1/tokens endpoints. An authenticated attacker can obtain a target's numeric user ID via authenticated user search, then create link shares on an attacker-writable project until the link-share sequence reaches that value, and use the resulting link-share JWT to list, create, and delete the target user's API tokens (including issuing a new token with attacker-chosen scopes under the target's permissions). Fixed in version 2.4.0.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Go	code.vikunja.io/api	2.4.0	GHSA-vvcv-vpph-h844
Go	code.vikunja.io/api	no fix listed	GO-2026-6753

Affected products (as reported)

Vendor	Product	Versions
go-vikunja	vikunja	0.22.0 – before 2.4.0

Weakness: CWE-863 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

References

GitHub Security Advisory (GHSA-vvcv-vpph-h844) vendor-advisory
Patch Commit patch
Patch Commit patch
VulnCheck Advisory: Vikunja 0.22.0 through 2.3.0 Authentication Bypass via Principal ID Collision third-party-advisory