CVE-2026-54896
Oj: Heap Buffer Overflow in Oj.dump Exception Serialization via Large Indent
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 object mode, Oj.dump is vulnerable to a heap buffer overflow when serializing Exception objects with a large :indent value. The serializer allocates a buffer sized for the object's attributes but does not account for the indent bytes added on each write. With indent: 5000, the accumulation of 5,000-byte indent strings overflows the 13,150-byte heap allocation, corrupting adjacent heap memory. This issue has been fixed in version 3.17.2.
INFO
Published Date :
July 1, 2026, 12:16 a.m.
Last Modified :
Oct. 25, 2026, 5:10 p.m.
Remotely Exploit :
No
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 4.0 | LOW | [email protected] |
Solution
- Update the Oj gem to version 3.17.2.
- Verify the installed gem version.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-54896.
| URL | Resource |
|---|---|
| https://github.com/ohler55/oj/security/advisories/GHSA-35w3-pjm6-wj95 | |
| https://github.com/ohler55/oj/security/advisories/GHSA-35w3-pjm6-wj95 |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-54896 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-54896
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-54896 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-54896 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Translated by [email protected]
Oct. 25, 2026
Action Type Old Value New Value Added Translation Title: oj de ohler55, Description: Oj (JSON Optimizado) es un analizador JSON y un serializador de objetos empaquetado como una gema de Ruby. En versiones anteriores a la 3.17.2, cuando está en modo objeto, Oj.dump es vulnerable a un desbordamiento de búfer de montón al serializar objetos Exception con un valor :indent grande. El serializador asigna un búfer dimensionado para los atributos del objeto, pero no tiene en cuenta los bytes de indentación añadidos en cada escritura. Con indent: 5000, la acumulación de cadenas de indentación de 5.000 bytes desborda la asignación de montón de 13.150 bytes, corrompiendo la memoria de montón adyacente. Este problema ha sido solucionado en la versión 3.17.2. -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jul. 01, 2026
Action Type Old Value New Value Added Reference https://github.com/ohler55/oj/security/advisories/GHSA-35w3-pjm6-wj95 Added SSVC {'id': 'CVE-2026-54896', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-07-01T12:39:05.040104Z'} -
New CVE Received by [email protected]
Jul. 01, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'ohler55', 'product': 'oj', 'versions': [{'status': 'affected', 'version': '< 3.17.2'}]}] Added 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 object mode, Oj.dump is vulnerable to a heap buffer overflow when serializing Exception objects with a large :indent value. The serializer allocates a buffer sized for the object's attributes but does not account for the indent bytes added on each write. With indent: 5000, the accumulation of 5,000-byte indent strings overflows the 13,150-byte heap allocation, corrupting adjacent heap memory. This issue has been fixed in version 3.17.2. Added CVSS V4.0 AV:L/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 Added CWE CWE-122 Added Reference https://github.com/ohler55/oj/security/advisories/GHSA-35w3-pjm6-wj95