CVE-2026-54500 - Vulnerability Details

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.

Published: 2026-06-30

Score: 5.3 Medium

EPSS: n/a

KEV: No

Impact:

Action:

Analysis

Analysis and contextual insights are available on OpenCVE Cloud.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

ohler55

affected

Version	Status	Constraints
`< 3.17.3`	affected	—

No data.

No data available yet.

Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories

Source	ID	Title
Github GHSA	GHSA-fm7p-mprw-wjm9	Oj: intern.c form_attr (uninitialized stack read)

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact Low

Integrity Impact None

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

References

Link	Providers
https://github.com/ohler55/oj/security/advisories/GHSA-fm7p-mprw-wjm9

History

Tue, 30 Jun 2026 23:45:00 +0000

Type	Values Removed	Values 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.
Title		Oj: intern.c form_attr has an uninitialized stack read
Weaknesses		CWE-125 CWE-908
References		https://github.com/ohler55/oj/security/advisories/GHSA-fm7p-mprw-wjm9
Metrics		cvssV3_1 `{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N'}`

Subscriptions

No data.

MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2026-06-30T23:08:28.789Z

Updated: 2026-06-30T23:08:28.789Z

Reserved: 2026-06-15T18:01:15.511Z

Link: CVE-2026-54500

Vulnrichment

No data.

NVD

No data.

Redhat

No data.

OpenCVE Enrichment

Updated: 2026-07-01T00:30:06Z

Weaknesses