Kirby: Access to image files and limited access to JSON files outside of the site root via path traversal in the media handling

{
  "id": "d6e3cbd2fc107a7cb969c2466cb02d8b837dc185e33ab933fa821918d08b1137",
  "url": "https://osv.dev/vulnerability/CVE-2026-75594",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Kirby: Access to image files and limited access to JSON files outside of the site root via path traversal in the media handling",
    "summary": "Kirby is an open-source content management system. Prior to 4.9.5 and 5.5.2, depending on the release line, Kirby's media handler in src/Cms/Media.php allowed Kirby\\Cms\\Media::thumb() to append a path-bearing filename to a validated parent media directory. On nginx, PHP's built-in server, or Apache with AllowEncodedSlashes enabled, a remote attacker could submit encoded slash characters such as %2f in the filename and traverse outside the parent's media directory. Differences between responses for existing and nonexistent thumbnail configurations disclosed whether an arbitrary .json file existed, and a .json file containing a valid filename key could cause the referenced image to be returned and the job file to be deleted. The related file::version path in src/Filesystem/Asset.php also accepted ../ sequences outside the intended index root. This issue is fixed in versions 4.9.5 and 5.5.2.",
    "evidence": "osv:CVE-2026-75594",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-75594",
      "aliases": [
        "CVE-2026-75594",
        "GHSA-9vx2-j98c-p72w"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/getkirby/kirby",
              "type": "GIT",
              "events": [
                {
                  "introduced": "2ff182ba39ddea19fa1615bd3733f734b5e53842"
                },
                {
                  "fixed": "81689c7f1471beb1fa9fb9c686f6f071f8671c3c"
                },
                {
                  "fixed": "22fbaedb7e6dd61f5def10829ba7bd7e73e0dcc9"
                },
                {
                  "fixed": "a40808f5c2ee5d42bb597fb6ffbe0de0ce8e4d20"
                },
                {
                  "fixed": "cd7abb68d298f3443eafd43fa2d0c7ad0f933d0e"
                },
                {
                  "fixed": "e0dca5f709adc21b36f5549df2c0619bc59da56c"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "5.0.0"
                      },
                      {
                        "fixed": "5.5.2"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "fixed": "22fbaedb7e6dd61f5def10829ba7bd7e73e0dcc9"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "a40808f5c2ee5d42bb597fb6ffbe0de0ce8e4d20"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "cd7abb68d298f3443eafd43fa2d0c7ad0f933d0e"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "e0dca5f709adc21b36f5549df2c0619bc59da56c"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "81689c7f1471beb1fa9fb9c686f6f071f8671c3c"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "5.5.2"
                  }
                ]
              }
            }
          ],
          "versions": [
            "5.5.1",
            "5.5.0",
            "5.4.4",
            "5.4.3",
            "5.4.2",
            "5.4.1",
            "5.4.0",
            "5.3.3",
            "5.3.2",
            "5.3.1",
            "5.3.0",
            "5.2.3",
            "5.2.2",
            "5.2.1",
            "5.2.0",
            "5.1.4",
            "5.1.3",
            "5.1.2",
            "5.1.1",
            "5.1.0",
            "5.0.4",
            "5.0.3",
            "5.0.2",
            "5.0.1",
            "5.0.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-75594.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:50.891149810Z",
      "provider": "osv",
      "references": [
        "https://github.com/getkirby/kirby/releases/tag/4.9.5",
        "https://github.com/getkirby/kirby/releases/tag/5.5.2",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/75xxx/CVE-2026-75594.json",
        "https://github.com/getkirby/kirby/security/advisories/GHSA-9vx2-j98c-p72w",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-75594",
        "https://github.com/getkirby/kirby/commit/22fbaedb7e6dd61f5def10829ba7bd7e73e0dcc9",
        "https://github.com/getkirby/kirby/commit/a40808f5c2ee5d42bb597fb6ffbe0de0ce8e4d20",
        "https://github.com/getkirby/kirby/commit/cd7abb68d298f3443eafd43fa2d0c7ad0f933d0e",
        "https://github.com/getkirby/kirby/commit/e0dca5f709adc21b36f5549df2c0619bc59da56c"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-22"
        ],
        "cna_assigner": "GitHub_M",
        "unresolved_ranges": [
          {
            "extracted_events": [
              {
                "range": [
                  {
                    "fixed": "4.9.5"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StringRangeExpression"
              }
            ]
          }
        ],
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/75xxx/CVE-2026-75594.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-75594",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 519373,
  "published_at": "2026-08-31T20:53:00.338+00:00"
}