Apache Fory PyFory Deserialization of Untrusted Data
Fory 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.
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | pyfory | >= 0.13.0, < 1.0.0 | 1.0.0 |
References
- https://nvd.nist.gov/vuln/detail/CVE-2026-48207
- https://fory.apache.org/security/#cve-2026-48207-pyfory-reduceserializer-deserializationpolicy-bypass
- https://github.com/apache/fory
- http://www.openwall.com/lists/oss-security/2026/05/21/10
- https://pypi.org/project/pyfory
- https://github.com/advisories/GHSA-m5gw-83w2-7749
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H- Weakness (CWE)
CWE-502- Platform
- Python (PyPI)
- Package
pyfory- Disclosed
- 21.05.2026
- Updated
- 11.10.2026 14:17
Sources and licenses
OSV / GitHub Advisory Database - PYSEC-2026-2984 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-m5gw-83w2-7749 - CC BY 4.0
Vulnerability history: pyfory
All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 2
- First → latest
- 10.2025 05.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Critical 2
Disclosures per year
- 2025: 1
- 2026: 1
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