CVE-2026-54592
Oj: Stack Buffer Overflow in Oj::Doc#each_child via Deeply Nested Input
Description
Oj (Optimized JSON) is a JSON parser and Object marshaller packaged as a Ruby gem. In versions prior to 3.17.3, Oj::Doc#each_child, when invoked recursively over a deeply nested JSON document, overflows a fixed-size stack buffer and aborts the process, leading to DoS. In a two-step chain in ext/oj/fast.c, doc_each_child increments doc->where past the where_path[MAX_STACK = 100] array with no bounds check and never restores it (the doc->where-- is missing), so calling each_child recursively from inside the yield block drives doc->where beyond the array. On the next entry the function copies the path into the 800-byte stack-local buffer save_path[MAX_STACK] using wlen = doc->where - doc->where_path, so when the previous recursive call left doc->where past where_path[100] the wlen exceeds MAX_STACK and the memcpy overflows save_path on the C stack; because the Oj::Doc parser imposes no JSON nesting-depth limit (relying on a C-stack pressure check), deeply nested attacker input reaches this path. This issue has been fixed in version 3.17.3.
INFO
Published Date :
July 1, 2026, 12:16 a.m.
Last Modified :
Oct. 25, 2026, 5:10 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | HIGH | [email protected] |
Solution
- Update the Oj gem to version 3.17.3.
- Ensure JSON nesting does not exceed limits.
- Review input validation for deeply nested structures.
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-2026-54592.
| URL | Resource |
|---|---|
| https://github.com/ohler55/oj/security/advisories/GHSA-3m6q-jj5j-38c9 | |
| https://github.com/ohler55/oj/security/advisories/GHSA-3m6q-jj5j-38c9 |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-54592 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-2026-54592
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-2026-54592 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-54592 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 Ruby. En versiones anteriores a la 3.17.3, Oj::Doc#each_child, cuando se invoca recursivamente sobre un documento JSON profundamente anidado, desborda un búfer de pila de tamaño fijo y aborta el proceso, lo que lleva a DoS. En una cadena de dos pasos en ext/oj/fast.c, doc_each_child incrementa doc -> where más allá del array where_path[MAX_STACK = 100] sin verificación de límites y nunca lo restaura (falta el doc -> where--), por lo que llamar a each_child recursivamente desde dentro del bloque yield lleva a doc -> where más allá del array. En la siguiente entrada, la función copia la ruta en el búfer local de pila de 800 bytes save_path[MAX_STACK] usando wlen = doc -> where - doc -> where_path, por lo que cuando la llamada recursiva anterior dejó doc -> where más allá de where_path[100], el wlen excede MAX_STACK y el memcpy desborda save_path en la pila C; debido a que el analizador Oj::Doc no impone un límite de profundidad de anidamiento JSON (confiando en una verificación de presión de la pila C), la entrada del atacante profundamente anidada alcanza esta ruta. Este problema ha sido solucionado en la versión 3.17.3. -
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-3m6q-jj5j-38c9 Added SSVC {'id': 'CVE-2026-54592', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'yes'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-07-01T12:35:37.238466Z'} -
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': '< 3.17.3'}]}] Added Description Oj (Optimized JSON) is a JSON parser and Object marshaller packaged as a Ruby gem. In versions prior to 3.17.3, Oj::Doc#each_child, when invoked recursively over a deeply nested JSON document, overflows a fixed-size stack buffer and aborts the process, leading to DoS. In a two-step chain in ext/oj/fast.c, doc_each_child increments doc->where past the where_path[MAX_STACK = 100] array with no bounds check and never restores it (the doc->where-- is missing), so calling each_child recursively from inside the yield block drives doc->where beyond the array. On the next entry the function copies the path into the 800-byte stack-local buffer save_path[MAX_STACK] using wlen = doc->where - doc->where_path, so when the previous recursive call left doc->where past where_path[100] the wlen exceeds MAX_STACK and the memcpy overflows save_path on the C stack; because the Oj::Doc parser imposes no JSON nesting-depth limit (relying on a C-stack pressure check), deeply nested attacker input reaches this path. This issue has been fixed in version 3.17.3. Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Added CWE CWE-125 Added CWE CWE-787 Added Reference https://github.com/ohler55/oj/security/advisories/GHSA-3m6q-jj5j-38c9