Vikunja: Scoped API token can mint unrestricted OAuth session credentials

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

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

EPSS

• CVE-2026-57458: 0.33% estimated exploitation activity in the next 30 days; percentile 26.22 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary A scoped API token can bypass its declared permissions by using the OAuth authorization flow to mint normal session credentials. A token limited to: can call /api/v1/oauth/authorize, receive an OAuth authorization code, exchange it at /api/v1/oauth/token, and obtain a normal bearer JWT plus refresh token. The resulting credentials are not restricted by the original API-token permissions. Affected Component Scoped API tokens OAuth authorization flow POST /api/v1/oauth/authorize POST /api/v1/oauth/token Impact A narrowly scoped API token with only oauth.authorize can be converted into normal session credentials for the same user. This bypasses the intended API-token permission boundary. An attacker who obtains or is delegated such a limited token can mint a normal JWT and refresh token, then access routes outside the original token scope. Runtime validation showed that the original scoped token could not access GET /api/v1/user, but the minted OAuth access token could access:…

Published by the source

9 Oct 2026, 20:40 UTC

Last modified by the source

19 Oct 2026, 21:31 UTC

Source last checked

26 Oct 2026, 15:32 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-v3p6-34mc-hj7v

2. Revision 2 · amended · 24 Oct 2026

   Amended from osv record GO-2026-6750

3. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-v3p6-34mc-hj7v

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# Patch Next advisory brief: CVE-2026-57458

Advisory: Vikunja: Scoped API token can mint unrestricted OAuth session credentials
IDs: CVE-2026-57458, GHSA-v3p6-34mc-hj7v
Record: https://patchnext.com/advisories/cve-2026-57458 (revision 3, source checked 26 Oct 2026, 15:32 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: code.vikunja.io/api 2.4.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go code.vikunja.io/api: affected >= 2.3.0, <= 2.3.0; fixed in 2.4.0

## Suggested inspection (read-only)
- Go code.vikunja.io/api: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on code.vikunja.io/api.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GO-2026-6750 (OSV record GO-2026-6750 lists affected ranges: Go code.vikunja.io/api >=0)
- Verified: https://osv.dev/vulnerability/GHSA-v3p6-34mc-hj7v (OSV record GHSA-v3p6-34mc-hj7v lists affected ranges: Go code.vikunja.io/api >=2.3.0 <2.4.0 (fixed))
- Verified: https://github.com/advisories/GHSA-v3p6-34mc-hj7v (GitHub-reviewed advisory GHSA-v3p6-34mc-hj7v lists affected ranges: Go code.vikunja.io/api >=2.3.0 <=2.3.0)

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