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.
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History
Wed, 01 Jul 2026 10:30:00 +0000
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Ohler
Ohler oj |
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Ohler
Ohler oj |
Tue, 30 Jun 2026 23:45:00 +0000
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| 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. | |
| Title | Oj: Negative-Size memcpy in Oj::Parser create_id Attribute Handling | |
| Weaknesses | CWE-190 CWE-787 |
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cvssV4_0
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Status: PUBLISHED
Assigner: GitHub_M
Published: 2026-06-30T23:34:05.904Z
Updated: 2026-06-30T23:34:05.904Z
Reserved: 2026-06-16T13:49:33.555Z
Link: CVE-2026-54900
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