Apache Fory PyFory Deserialization of Untrusted Data

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

9.8 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS

• CVE-2026-48207: 0.57% estimated exploitation activity in the next 30 days; percentile 47.47 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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.

Published by the source

21 May 2026, 18:33 UTC

Last modified by the source

13 Jul 2026, 16:42 UTC

Source last checked

26 Oct 2026, 13:46 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-m5gw-83w2-7749

2. Revision 2 · amended · 24 Oct 2026

   Amended from osv record GHSA-m5gw-83w2-7749

3. Revision 1 · created · 23 Oct 2026

   Published from ghsa record GHSA-m5gw-83w2-7749

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# Patch Next advisory brief: CVE-2026-48207

Advisory: Apache Fory PyFory Deserialization of Untrusted Data
IDs: CVE-2026-48207, GHSA-m5gw-83w2-7749
Record: https://patchnext.com/advisories/cve-2026-48207 (revision 3, source checked 26 Oct 2026, 13:46 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 9.8)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: pyfory 1.0.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI pyfory: affected >= 0.13.0, < 1.0.0; fixed in 1.0.0

## Suggested inspection (read-only)
- `python -m pip show pyfory`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on pyfory.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-m5gw-83w2-7749 (GitHub-reviewed advisory GHSA-m5gw-83w2-7749 lists affected ranges: PyPI pyfory >=0.13.0 <1.0.0)
- Verified: https://osv.dev/vulnerability/GHSA-m5gw-83w2-7749 (OSV record GHSA-m5gw-83w2-7749 lists affected ranges: PyPI pyfory >=0.13.0 <1.0.0 (fixed))

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