Apache Fory: PyFory ReduceSerializer Incomplete Policy Enforcement

{
  "id": "1923559c2b00e1e8268aa4a88eefd4c7e0dcf6890fae187277f87ba60f18f442",
  "url": "https://osv.dev/vulnerability/CVE-2026-48207",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Apache Fory: PyFory ReduceSerializer Incomplete Policy Enforcement",
    "summary": "Deserialization of untrusted data in Apache Fory PyFory. PyFory's ReduceSerializer could bypass documented DeserializationPolicy validation hooks during reduce-state restoration and global-name resolution. An application is vulnerable if it deserializes attacker-controlled data using PyFory Python-native mode with strict mode disabled and relies on DeserializationPolicy to restrict unsafe classes, functions, or module attributes. This issue affects Apache Fory: from before 1.0.0. Mitigation: Users of Apache Fory are recommended to upgrade to version 1.0.0 or later, which enforces DeserializationPolicy validation for the affected ReduceSerializer paths and thus fixes this issue.",
    "evidence": "osv:CVE-2026-48207",
    "products": [],
    "severity": "critical",
    "structured": {
      "id": "CVE-2026-48207",
      "aliases": [
        "CVE-2026-48207",
        "GHSA-m5gw-83w2-7749",
        "PYSEC-2026-2984"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/apache/fory",
              "type": "GIT",
              "events": [
                {
                  "introduced": "471a646d2d3c3aad32870c76e986dc19b51de6d4"
                },
                {
                  "fixed": "36a01b6253d5974f13be3258205ac13f0ceaee44"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:apache:fory:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0.13.0"
                      },
                      {
                        "fixed": "1.0.0"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-48207.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:30.609873058Z",
      "provider": "osv",
      "references": [
        "https://pypi.org/",
        "https://fory.apache.org/security/#cve-2026-48207-pyfory-reduceserializer-deserializationpolicy-bypass",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/48xxx/CVE-2026-48207.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-48207"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-502"
        ],
        "cna_assigner": "apache",
        "unresolved_ranges": [
          {
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "0.13.0"
                  },
                  {
                    "fixed": "1.0.0"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StandardRange"
              }
            ]
          }
        ],
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/48xxx/CVE-2026-48207.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-48207",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 497757,
  "published_at": "2026-05-21T15:51:12.292+00:00"
}