Misskey: Improper Authorization in the Announcements API

{
  "id": "0bb6c8ae195757421e378055be389192a9bbba86c08d27a6714a1eef0b5b92fd",
  "url": "https://osv.dev/vulnerability/CVE-2026-48115",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Misskey: Improper Authorization in the Announcements API",
    "summary": "Misskey is an open source, federated social media platform. All Misskey servers running versions 2024.5.0 and later, but prior to 2026.5.4, contain a vulnerability in the Server Announcements API where insufficient permission checks allow attackers to access limited portions of data that they normally couldn't view. This vulnerability occurs whether or not federation is enabled. This issue has been fixed in version 2026.5.4.",
    "evidence": "osv:CVE-2026-48115",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-48115",
      "aliases": [
        "CVE-2026-48115",
        "GHSA-j49q-76hx-mv8f"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/misskey-dev/misskey",
              "type": "GIT",
              "events": [
                {
                  "introduced": "6078081c336ab42535cbea173c728d2aef08d5d2"
                },
                {
                  "fixed": "4aa1d9ffc851a7824cb72b84ec01c3f65613463c"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "2024.5.0"
                      },
                      {
                        "fixed": "2026.5.4"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "fixed": "4aa1d9ffc851a7824cb72b84ec01c3f65613463c"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "2026.5.4"
                  },
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "2026.5.4"
                      }
                    ],
                    "source": "DESCRIPTION"
                  }
                ]
              }
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-48115.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:36.747417203Z",
      "provider": "osv",
      "references": [
        "https://github.com/misskey-dev/misskey/releases/tag/2026.5.4",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/48xxx/CVE-2026-48115.json",
        "https://github.com/misskey-dev/misskey/security/advisories/GHSA-j49q-76hx-mv8f",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-48115"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-285"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/48xxx/CVE-2026-48115.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-48115",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 504009,
  "published_at": "2026-08-03T21:21:59.281+00:00"
}