GHSA-94XM-JJ8X-3CR4

Vulnerability from github – Published: 2026-03-25 21:10 – Updated: 2026-03-25 21:10
VLAI?
Summary
Vikunja Allows Disabled/Locked User Accounts to Authenticate via API Tokens, CalDAV, and OpenID Connect
Details

Summary

When a user account is disabled or locked, the status check is only enforced on the local login and JWT token refresh paths. Three other authentication paths — API tokens, CalDAV basic auth, and OpenID Connect — do not verify user status, allowing disabled or locked users to continue accessing the API and syncing data.

Details

User status (StatusDisabled, StatusAccountLocked) is checked in only two places:

  1. Local/LDAP login (pkg/routes/api/v1/login.go:74) — prevents issuing new JWTs
  2. JWT token refresh (pkg/routes/api/v1/login.go:247) — prevents refreshing expired JWTs

Three other authentication paths fetch the user from the database via GetUserByID but never inspect the returned user's status:

1. API Token Authentication (pkg/routes/api_tokens.go:76-103)

API tokens are long-lived (up to years) and have no refresh cycle. A disabled user's API tokens remain fully functional until they expire naturally.

2. CalDAV Basic Auth (pkg/routes/caldav/auth.go)

The CalDAV basic auth handler validates credentials but does not check user status before granting access. A disabled user with valid credentials or a CalDAV token can continue syncing calendars and tasks.

3. OpenID Connect Callback (pkg/modules/auth/openid/openid.go)

The OIDC callback issues a fresh JWT token after validating the identity provider's response but does not check whether the Vikunja user account is disabled. If the user's identity provider session is still active, they receive a valid JWT despite being disabled in Vikunja.

Impact

An administrator who disables a user account expects that user to be immediately locked out. In practice:

  • API tokens: The user retains full API access for the remaining lifetime of any issued API tokens — potentially months or years.
  • CalDAV: The user can continue reading and writing tasks/events via any CalDAV client.
  • OIDC: The user can obtain a fresh, fully valid JWT by re-authenticating through their identity provider, completely bypassing the account disable.

Proof of Concept

  1. Create a user and generate an API token.
  2. Disable the user account via the admin API or CLI.
  3. Make an API request using the API token: bash curl -H "Authorization: Bearer tk_<token>" https://vikunja.example/api/v1/user
  4. The request succeeds with a 200 response despite the account being disabled.
Severity ?
7.1 (High)
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
Show details on source website
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{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 2.2.0"
      },
      "package": {
        "ecosystem": "Go",
        "name": "code.vikunja.io/api"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.18.0"
            },
            {
              "fixed": "2.2.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-33668"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-285"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-03-25T21:10:05Z",
    "nvd_published_at": "2026-03-24T16:16:34Z",
    "severity": "HIGH"
  },
  "details": "## Summary\n\nWhen a user account is disabled or locked, the status check is only enforced on the local login and JWT token refresh paths. Three other authentication paths \u2014 API tokens, CalDAV basic auth, and OpenID Connect \u2014 do not verify user status, allowing disabled or locked users to continue accessing the API and syncing data.\n\n## Details\n\nUser status (`StatusDisabled`, `StatusAccountLocked`) is checked in only two places:\n\n1. **Local/LDAP login** (`pkg/routes/api/v1/login.go:74`) \u2014 prevents issuing new JWTs\n2. **JWT token refresh** (`pkg/routes/api/v1/login.go:247`) \u2014 prevents refreshing expired JWTs\n\nThree other authentication paths fetch the user from the database via `GetUserByID` but never inspect the returned user\u0027s status:\n\n### 1. API Token Authentication (`pkg/routes/api_tokens.go:76-103`)\n\nAPI tokens are long-lived (up to years) and have no refresh cycle. A disabled user\u0027s API tokens remain fully functional until they expire naturally.\n\n### 2. CalDAV Basic Auth (`pkg/routes/caldav/auth.go`)\n\nThe CalDAV basic auth handler validates credentials but does not check user status before granting access. A disabled user with valid credentials or a CalDAV token can continue syncing calendars and tasks.\n\n### 3. OpenID Connect Callback (`pkg/modules/auth/openid/openid.go`)\n\nThe OIDC callback issues a fresh JWT token after validating the identity provider\u0027s response but does not check whether the Vikunja user account is disabled. If the user\u0027s identity provider session is still active, they receive a valid JWT despite being disabled in Vikunja.\n\n## Impact\n\nAn administrator who disables a user account expects that user to be immediately locked out. In practice:\n\n- **API tokens**: The user retains full API access for the remaining lifetime of any issued API tokens \u2014 potentially months or years.\n- **CalDAV**: The user can continue reading and writing tasks/events via any CalDAV client.\n- **OIDC**: The user can obtain a fresh, fully valid JWT by re-authenticating through their identity provider, completely bypassing the account disable.\n\n## Proof of Concept\n\n1. Create a user and generate an API token.\n2. Disable the user account via the admin API or CLI.\n3. Make an API request using the API token:\n   ```bash\n   curl -H \"Authorization: Bearer tk_\u003ctoken\u003e\" https://vikunja.example/api/v1/user\n   ```\n4. The request succeeds with a 200 response despite the account being disabled.",
  "id": "GHSA-94xm-jj8x-3cr4",
  "modified": "2026-03-25T21:10:05Z",
  "published": "2026-03-25T21:10:05Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/go-vikunja/vikunja/security/advisories/GHSA-94xm-jj8x-3cr4"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-33668"
    },
    {
      "type": "WEB",
      "url": "https://github.com/go-vikunja/vikunja/commit/033922309f492996c928122fb49b691339199c35"
    },
    {
      "type": "WEB",
      "url": "https://github.com/go-vikunja/vikunja/commit/04704e0fde4b027039cf583110cee7afe136fc1b"
    },
    {
      "type": "WEB",
      "url": "https://github.com/go-vikunja/vikunja/commit/0b04768d830c80e9fde1b0962db1499cc652da0e"
    },
    {
      "type": "WEB",
      "url": "https://github.com/go-vikunja/vikunja/commit/fd452b9cb6457fd4f9936527a14c359818f1cca7"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/go-vikunja/vikunja"
    },
    {
      "type": "WEB",
      "url": "https://vikunja.io/changelog/vikunja-v2.2.2-was-released"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Vikunja Allows Disabled/Locked User Accounts to Authenticate via API Tokens, CalDAV, and OpenID Connect"
}


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