CVE-2026-54901

MEDIUM

Oj: Use-After-Free in Oj::Parser array_class/hash_class GC Marking

Title source: cna
STIX 2.1

Exploitation Summary

EIP tracks 1 public exploit for CVE-2026-54901. PoCs published by HermesNA-1.

AI-analyzed exploit summary This repository contains an auto-generated stub module for CVE-2026-54901, a garbage collection issue in the Oj Ruby gem (versions prior to 3.17.2) where `Oj::Parser` fails to mark `array_class` and `hash_class` references. The code includes placeholder methods (`check`, `run`) but lacks actual exploit logic or PoC implementation.

Description

Oj (Optimized JSON) is a JSON parser and Object marshaller packaged as a Ruby gem. In versions prior to 3.17.2, Oj::Parser in usual mode does not mark array_class and hash_class references during garbage collection, leading to Use-After-Free. If GC runs after the class is assigned but before a parse, the class object is reclaimed, leaving the parser holding a dangling VALUE. The subsequent parse call dereferences the freed object, producing a segfault. This issue has been fixed in version 3.17.2.

Exploits (1)

github STUB 1 stars
by HermesNA-1 · pythonpoc
https://github.com/HermesNA-1/SnakeSploit/tree/main/data/modules_generated/cve-2026-54901_optimized_json.py

This repository contains an auto-generated stub module for CVE-2026-54901, a garbage collection issue in the Oj Ruby gem (versions prior to 3.17.2) where `Oj::Parser` fails to mark `array_class` and `hash_class` references. The code includes placeholder methods (`check`, `run`) but lacks actual exploit logic or PoC implementation.

Classification
Stub 99%
Attack Type
Other
Complexity
Complex
Reliability
Theoretical
Target: Oj (Optimized JSON) Ruby gem < 3.17.2
No auth needed
Prerequisites: Target must be running a vulnerable version of the Oj gem (< 3.17.2) · Network access to the target service parsing JSON input
mistral-large-3 · analyzed Jul 09, 2026 Full analysis →

References (1)

Core 1
Core References

Scores

CVSS v4 6.3
EPSS 0.0025
EPSS Percentile 16.8%
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CISA SSVC

Vulnrichment
Exploitation poc
Automatable no
Technical Impact partial

Details

CWE
CWE-416
Status published
Products (1)
ohler55/oj < 3.17.2
Published Jul 01, 2026
Tracked Since Jul 01, 2026