GHSA-m5gw-83w2-7749 — critical GitHub Advisory (CVE-2026-48207) in pip/pyfory

Description

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.

Basic information

Type: reviewed
Severity: critical
Advisory on GitHub: Open advisory ↗
Repository advisory: —
Source code: Browse source ↗
Published (advisory): 2026-05-21 18:33:09 UTC
Updated: 2026-06-30 21:44:46 UTC
GitHub reviewed: 2026-06-30 21:44:43 UTC
NVD published: 2026-05-21

Score	Percentile
0.57%	42.86%

CVSS Scores

Base score	Version	Severity	Vector
9.8	3.1	—	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:H) Serious risk that confidential data gets exposed in a big way. Integrity (I:H) They could widely tamper with or forge data—trust in the data is badly hurt. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.

Identifiers

Type	Value
GHSA	GHSA-m5gw-83w2-7749 ↗
CVE	CVE-2026-48207 ↗

CWEs

CWE id	Name
CWE-502	Deserialization of Untrusted Data

Credits

HGWAYEN (analyst)

Affected packages (1)

Vulnerable version ranges and first patched releases as published by GitHub.

Ecosystem	Package	Vulnerable range	First patched	Vulnerable functions
pip	pyfory	>= 0.13.0, < 1.0.0	1.0.0	—

Apache Fory PyFory Deserialization of Untrusted Data