CVE-2026-54903

MEDIUM

Oj: Integer Overflow in Oj.load 2GB String Handling

Title source: cna
STIX 2.1

Exploitation Summary

EIP tracks 1 public exploit for CVE-2026-54903. PoCs published by HermesNA-1.

AI-analyzed exploit summary This repository contains an auto-generated stub module for CVE-2026-54903, a heap corruption vulnerability in the Oj Ruby gem (versions prior to 3.17.2) when parsing JSON strings longer than 2 GB. The code includes placeholder methods (`check` and `run`) but lacks actual exploit implementation or technical details.

Description

Oj (Optimized JSON) is a JSON parser and Object marshaller packaged as a Ruby gem. In versions prior to 3.17.2, Oj.load is vulnerable to heap corruption when parsing a JSON string longer than 2 GB. An integer overflow in buf_append_string (buf.h:61) converts the string length to a large negative size_t, causing memcpy to copy an astronomically large amount of data out of bounds. This crashes the process and can corrupt adjacent heap memory. The 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-2026-54903_optimized_json.py

This repository contains an auto-generated stub module for CVE-2026-54903, a heap corruption vulnerability in the Oj Ruby gem (versions prior to 3.17.2) when parsing JSON strings longer than 2 GB. The code includes placeholder methods (`check` and `run`) but lacks actual exploit implementation or technical details.

Classification
Stub 98%
Attack Type
Dos
Complexity
Moderate
Reliability
Theoretical
Target: Oj (Optimized JSON) Ruby gem versions prior to 3.17.2
No auth needed
Prerequisites: Network access to a service using the vulnerable Oj gem for JSON parsing · Ability to send a JSON payload >2 GB
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 yes
Technical Impact partial

Details

CWE
CWE-190
Status published
Products (1)
ohler55/oj < 3.17.2
Published Jul 01, 2026
Tracked Since Jul 01, 2026