CVE-2026-54900

MEDIUM

Oj: Negative-Size memcpy in Oj::Parser create_id Attribute Handling

Title source: cna
STIX 2.1

Exploitation Summary

EIP tracks 2 public exploits for CVE-2026-54900. PoCs published by HermesNA-1, HORKimhab.

AI-analyzed exploit summary This repository contains an auto-generated placeholder module for CVE-2026-54900, a heap corruption vulnerability in the Oj (Optimized JSON) Ruby gem versions prior to 3.17.2. The code includes only a basic connectivity check and a TODO stub for exploit implementation, with no actual exploit logic or technical details about the vulnerability mechanics.

Description

Oj (Optimized JSON) is a JSON parser and Object marshaller packaged as a Ruby gem. In versions prior to 3.17.2, when in usual mode with create_id enabled, Oj::Parser#parse is vulnerable to heap corruption via a negative-size memcpy. When a JSON object key is exactly 65,535 bytes long, an integer truncation in form_attr (usual.c:63) converts the length to -1 before passing it to memcpy. This causes memcpy to copy SIZE_MAX bytes (interpreted as a huge size_t), corrupting heap memory and crashing the process. The issue has been fixed in version 3.17.2.

Exploits (2)

github STUB 1 stars
by HermesNA-1 · pythonpoc
https://github.com/HermesNA-1/SnakeSploit/tree/main/data/modules_generated/cve-2026-54900_optimized_json.py

This repository contains an auto-generated placeholder module for CVE-2026-54900, a heap corruption vulnerability in the Oj (Optimized JSON) Ruby gem versions prior to 3.17.2. The code includes only a basic connectivity check and a TODO stub for exploit implementation, with no actual exploit logic or technical details about the vulnerability mechanics.

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 Oj gem (< 3.17.2) · Target must have create_id enabled in usual mode · Network connectivity to target service parsing JSON input
mistral-large-3 · analyzed Jul 09, 2026 Full analysis →
github STUB
by HORKimhab · poc
https://github.com/HORKimhab/CVE-2026-54900

This repository contains no actual exploit code, technical details, or proof-of-concept for CVE-2026-54900. It only includes a README with donation requests, legal disclaimers, and placeholder instructions without any functional implementation.

Classification
Stub 95%
Attack Type
Other
Complexity
Trivial
Reliability
Theoretical
Target: unspecified
No auth needed
mistral-large-3 · analyzed Jul 25, 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 total

Details

CWE
CWE-190 CWE-787
Status published
Products (1)
ohler55/oj < 3.17.2
Published Jul 01, 2026
Tracked Since Jul 01, 2026