BookWyrm through 0.9.1 Missing Authorization on the Favorite and Unfavorite Endpoints

{
  "id": "ba81a1c8b6cf3a42e153c59ae091129b77added17ed85a7ae7155ee0596e82a5",
  "url": "https://osv.dev/vulnerability/CVE-2026-86112",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "BookWyrm through 0.9.1 Missing Authorization on the Favorite and Unfavorite Endpoints",
    "summary": "BookWyrm through 0.9.1 fails to validate user visibility permissions in the Favorite and Unfavorite views, allowing authenticated attackers to favorite or unfavorite followers-only and direct statuses they cannot access. Attackers can POST to the favorite endpoint with a status ID to create unauthorized interactions, trigger ActivityPub broadcasts, and enumerate private status IDs through response differentiation.",
    "evidence": "osv:CVE-2026-86112",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-86112",
      "aliases": [
        "CVE-2026-86112"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/bookwyrm-social/bookwyrm",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "last_affected": "f4246d246d474939298fb49d715904ea38b4cb81"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "last_affected": "0.9.1"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "last_affected": "0.9.1"
                      }
                    ],
                    "source": "DESCRIPTION"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v0.9.1",
            "v0.9.0",
            "v0.8.7",
            "v0.8.6",
            "v0.7.4",
            "v0.7.3",
            "v0.7.2",
            "v0.7.1",
            "v0.6.6",
            "v0.6.5",
            "v0.6.4",
            "v0.6.3",
            "v0.6.2",
            "v0.6.1",
            "v0.6.0",
            "v0.5.5",
            "v0.5.4",
            "v0.5.3",
            "v0.5.2",
            "v0.5.1",
            "v0.5.0",
            "v0.4.6",
            "v0.4.5",
            "v0.4.4",
            "v0.4.3",
            "v0.4.2",
            "0.4.2",
            "v0.4.1",
            "v0.4.0",
            "v0.3.4",
            "v0.3.3",
            "v0.3.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-86112.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:27.847250087Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/86xxx/CVE-2026-86112.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-86112",
        "https://www.vulncheck.com/advisories/bookwyrm-through-0.9.1-missing-authorization-on-the-favorite-and-unfavorite-endpoints",
        "https://github.com/bookwyrm-social/bookwyrm",
        "https://github.com/bookwyrm-social/bookwyrm/blob/v0.9.1/bookwyrm/views/interaction.py",
        "https://github.com/geo-chen/oss/blob/main/bookwyrm.md#finding-2-authenticated-idor-in-favoriteunfavorite-allows-interaction-with-private-statuses"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-639"
        ],
        "cna_assigner": "VulnCheck",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/86xxx/CVE-2026-86112.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-86112",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 494360,
  "published_at": "2026-09-05T09:59:04.004+00:00"
}