Gitea private attachment disclosure through repository mismatch

{
  "id": "f311293609989268a957d899746b5b9ae316275dbbeb39c05a947918bfee2301",
  "url": "https://osv.dev/vulnerability/CVE-2026-78433",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Gitea private attachment disclosure through repository mismatch",
    "summary": "Gitea's web attachment handler skips its cross-repository ownership check for attachments created before 16 January 2026 and checks permissions against the repository named in the request URL instead. An unauthenticated attacker who knows a private attachment's UUID can request it through a public repository's attachment path and retrieve its contents. This can expose issue and pull request attachments or release assets; the random attachment UUID must already be known to the attacker.",
    "evidence": "osv:CVE-2026-78433",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-78433",
      "aliases": [
        "CVE-2026-78433",
        "GHSA-frpv-2xgv-wxpq"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/go-gitea/gitea",
              "type": "GIT",
              "events": [
                {
                  "introduced": "f09bea7af13bd00d07a34252468389d15de39a8d"
                },
                {
                  "fixed": "146cc3eec57174711eac0e0a0c7b38670c6e3922"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "1.26.0"
                      },
                      {
                        "last_affected": "1.27.2"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "range": [
                      {
                        "fixed": "146cc3eec57174711eac0e0a0c7b38670c6e3922"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "v1.27.3"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v1.27.2",
            "v1.27.1",
            "v1.27.0",
            "v1.27.0-rc0",
            "v1.28.0-dev",
            "v1.27.0-dev",
            "v1.26.0-dev"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-78433.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:26.879191789Z",
      "provider": "osv",
      "references": [
        "https://blog.gitea.com/release-of-1.27.3/",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/78xxx/CVE-2026-78433.json",
        "https://github.com/go-gitea/gitea/releases/tag/v1.27.3",
        "https://github.com/go-gitea/gitea/security/advisories/GHSA-frpv-2xgv-wxpq",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-78433",
        "https://github.com/go-gitea/gitea/pull/39048",
        "https://github.com/go-gitea/gitea/pull/39077"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-1220",
          "CWE-284",
          "CWE-639",
          "CWE-863"
        ],
        "cna_assigner": "Gitea",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/78xxx/CVE-2026-78433.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-78433",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 493552,
  "published_at": "2026-10-14T14:38:17.247+00:00"
}