CVE-2023-22488: Flarum/core Flarum Notifications Can Leak Restricted Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-8gcg-vwmw-rxj4",
  "modified" : "2023-01-23T18:52:11Z",
  "published" : "2023-01-10T22:27:13Z",
  "aliases" : [ "CVE-2023-22488" ],
  "summary" : "Flarum notifications can leak restricted content",
  "details" : "Using the notifications feature, one can read restricted/private content and bypass access checks that would be in place for such content.\n\nThe notification-sending component does not check that the subject of the notification can be seen by the receiver, and proceeds to send notifications through their different channels. The alerts do not leak data despite this as they are listed based on a visibility check, however, emails are still sent out.\n\nThis means that, for extensions which restrict access to posts, any actor can bypass the restriction by subscribing to the discussion if the [*Subscriptions*](https://extiverse.com/extension/flarum/subscriptions) extension is enabled.\n\n### Impact\nThe attack allows the leaking of some posts in the forum database, including posts awaiting approval, posts in tags the user has no access to if they could subscribe to a discussion before it becomes private, and posts restricted by third-party extensions.\n\nOther leaks could also happen for different notification subjects if some features allowed to receive specific types of notifications for restricted content.\n\nAll Flarum versions prior to v1.6.3 are affected.\n\n### Patches\nThe vulnerability has been fixed and published as flarum/core v1.6.3. All communities running Flarum should upgrade as soon as possible to v1.6.3 using:\n\n```\ncomposer update --prefer-dist --no-dev -a -W\n```\nYou can then confirm you run the latest version using:\n\n```\ncomposer show flarum/core\n```\n\n### Workarounds\nDisable the Flarum Subscriptions extension or disable email notifications altogether.\n\n**There is no other supported workaround for this issue for Flarum versions below 1.6.3.**\n\n### For more information\nFor any questions or comments on this vulnerability please visit https://discuss.flarum.org/\n\nFor support questions create a discussion at https://discuss.flarum.org/t/support.\n\nA reminder that if you ever become aware of a security issue in Flarum, please report it to us privately by emailing [security@flarum.org](mailto:security@flarum.org), and we will address it promptly.\n",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:N/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "flarum/core"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.6.3"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/flarum/framework/security/advisories/GHSA-8gcg-vwmw-rxj4"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2023-22488"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/flarum/framework/commit/d0a2b95dca57d3dae9a0d77b610b1cb1d0b1766a"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/flarum/framework"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/flarum/framework/releases/tag/v1.6.3"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-862" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2023-01-10T22:27:13Z",
    "nvd_published_at" : "2023-01-12T20:15:00Z"
  }
}