Nextcloud: Files drop share links for end-to-end encrypted folders allowed to drop files into other folders of the share owner

{
  "id": "36477cc66632e2186aa4aa76b3f3d70aabe91a8d188a3fb6f51be38533ed0cc8",
  "url": "https://osv.dev/vulnerability/CVE-2026-45159",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Nextcloud: Files drop share links for end-to-end encrypted folders allowed to drop files into other folders of the share owner",
    "summary": "Nextcloud is an open source content collaboration platform. From versions 1.15.0 to before 1.15.4, 1.16.0 to before 1.16.3, 1.17.0 to before 1.17.1, and 1.18.0 to before 1.18.1, a malicious user with access to an end-to-end encrypted files drop link was able to also drop files into other end-to-end encrypted folders of the share owner. Reading and modifying of other files was not possible. This issue has been patched in versions 1.15.4, 1.16.3, 1.17.1, 1.18.1, and 2.0.0-rc.7.",
    "evidence": "osv:CVE-2026-45159",
    "products": [],
    "severity": "low",
    "structured": {
      "id": "CVE-2026-45159",
      "aliases": [
        "CVE-2026-45159",
        "GHSA-p3qw-7gwx-wg24"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/nextcloud/end_to_end_encryption",
              "type": "GIT",
              "events": [
                {
                  "introduced": "addcec302503339a0c3863eed1a5c956ab7576ff"
                },
                {
                  "fixed": "43084940199065937d5effc943bd91dba68d77f8"
                },
                {
                  "introduced": "b0375ec86af6d33787dfd63103ee35a062cbe7c8"
                },
                {
                  "fixed": "dae215821148c467187221e75504152d86bbfa8d"
                },
                {
                  "introduced": "e3accd7600254c5b57b2921d486195a1cf57074a"
                },
                {
                  "fixed": "cc2f53e44c892a4c6bf00d528f13080e38cd8fd8"
                },
                {
                  "introduced": "8c50b5c3e600c29fb570a4874b16a48f882dc423"
                },
                {
                  "fixed": "4b52b319faa729a1d00709c0545f179ba0866459"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "1.15.0"
                      },
                      {
                        "fixed": "1.15.4"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "introduced": "1.16.0"
                      },
                      {
                        "fixed": "1.16.3"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "introduced": "1.17.0"
                      },
                      {
                        "fixed": "1.17.1"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "introduced": "1.18.0"
                      },
                      {
                        "fixed": "1.18.1"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v1.18.0",
            "v1.15.3",
            "v1.16.2",
            "v1.17.0",
            "v1.16.1",
            "v1.16.0",
            "v1.15.2",
            "v1.15.1",
            "v1.15.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-45159.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:23.050614799Z",
      "provider": "osv",
      "references": [
        "https://hackerone.com/reports/3304830",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/45xxx/CVE-2026-45159.json",
        "https://github.com/nextcloud/security-advisories/security/advisories/GHSA-p3qw-7gwx-wg24",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-45159",
        "https://github.com/nextcloud/end_to_end_encryption/pull/1395"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-639"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/45xxx/CVE-2026-45159.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-45159",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 489617,
  "published_at": "2026-06-01T16:39:38.836+00:00"
}