CVE-2026-54500
Oj: intern.c form_attr has an uninitialized stack read
Description
Oj (Optimized JSON) is a JSON parser and Object marshaller packaged as a Ruby gem. In versions prior to 3.17.3, Oj.load in :object mode reads uninitialized stack memory (and, for long keys, reads out of bounds) when parsing a JSON object whose key is 254 bytes or longer. The interned bytes can surface to the caller, disclosing process stack memory. In ext/oj/intern.c, form_attr() handles the long-key path by allocating a heap buffer, `b`, populating it with the attribute name, and then freeing it — but it passed the uninitialized stack buffer buf (not b) to rb_intern3(). rb_intern3 therefore reads len + 1 bytes of uninitialized stack memory. When the key length is >= 256, it also reads out of bounds past the 256-byte buf. The resulting bytes are interned and can reach the caller via the produced Symbol or via the EncodingError message raised on invalid UTF-8, leaking process stack contents. 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 | MEDIUM | [email protected] |
Solution
- Update the Oj gem to version 3.17.3 or later.
- Ensure parsing handles keys correctly.
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-2026-54500.
| URL | Resource |
|---|---|
| https://github.com/ohler55/oj/security/advisories/GHSA-fm7p-mprw-wjm9 |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-54500 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-2026-54500
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-2026-54500 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-54500 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.
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CVE Translated by [email protected]
Oct. 25, 2026
Action Type Old Value New Value Added Translation Title: oj de ohler55, Description: Oj (Optimized JSON) es un analizador JSON y un serializador de objetos empaquetado como una gema de Ruby. En versiones anteriores a la 3.17.3, Oj.load en modo :object lee memoria de pila no inicializada (y, para claves largas, lee fuera de los límites) al analizar un objeto JSON cuya clave tiene 254 bytes o más. Los bytes internados pueden llegar al llamador, revelando la memoria de pila del proceso. En ext/oj/intern.c, form_attr() maneja la ruta de clave larga asignando un búfer en el heap, ’b’, rellenándolo con el nombre del atributo y luego liberándolo - pero pasó el búfer de pila no inicializado buf (no ’b’) a rb_intern3(). rb_intern3, por lo tanto, lee len + 1 bytes de memoria de pila no inicializada. Cuando la longitud de la clave es >= 256, también lee fuera de los límites más allá del búfer buf de 256 bytes. Los bytes resultantes son internados y pueden llegar al llamador a través del Símbolo producido o a través del mensaje de EncodingError generado por UTF-8 no válido, filtrando el contenido de la pila del proceso. 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 SSVC {'id': 'CVE-2026-54500', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'yes'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-07-01T13:34:29.080763Z'} -
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.load in :object mode reads uninitialized stack memory (and, for long keys, reads out of bounds) when parsing a JSON object whose key is 254 bytes or longer. The interned bytes can surface to the caller, disclosing process stack memory. In ext/oj/intern.c, form_attr() handles the long-key path by allocating a heap buffer, `b`, populating it with the attribute name, and then freeing it — but it passed the uninitialized stack buffer buf (not b) to rb_intern3(). rb_intern3 therefore reads len + 1 bytes of uninitialized stack memory. When the key length is >= 256, it also reads out of bounds past the 256-byte buf. The resulting bytes are interned and can reach the caller via the produced Symbol or via the EncodingError message raised on invalid UTF-8, leaking process stack contents. 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:L/I:N/A:N Added CWE CWE-125 Added CWE CWE-908 Added Reference https://github.com/ohler55/oj/security/advisories/GHSA-fm7p-mprw-wjm9