CVE-2026-54500

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 surfac...

CVE-2026-54899

Oj Optimized JSON is a JSON parser and Object marshaller packaged as a Ruby gem. Prior to version 3.17.2, disabling symbolkeys on a reused Oj::Parser instance triggers a heap use-after-free. When symbolkeys is toggled from true to false, optsymbolkeysset frees the internal key cache cachefree but...

GHSA-475M-PH3X-64GP Oj: Integer Overflow in Oj.load 2GB String Handling

Summary Oj.load is vulnerable to heap corruption when parsing a JSON string longer than 2 GB. An integer overflow in bufappendstring buf.h:61 converts the string length to a large negative sizet, causing memcpy to copy an astronomically large amount of data out of bounds. This crashes the process...

Oj: Use-After-Free in Oj::Parser SAJ Long Key Callback

Summary Oj::Parser in SAJ mode does not protect cached object keys ≥ 35 bytes from garbage collection. A Ruby callback that triggers GC inside hashend can cause the key string to be reclaimed while the C parser still holds a pointer to it. The subsequent access to the freed string VALUE results i...

GHSA-VWM4-62GF-X745 Oj: Use-After-Free in Oj::Parser array_class/hash_class GC Marking

Summary Oj::Parser in usual mode does not mark arrayclass and hashclass references during garbage collection. If GC runs after the class is assigned but before a parse, the class object is reclaimed, leaving the parser holding a dangling VALUE. The subsequent parse call dereferences the freed...

GHSA-9CV6-QCJW-4GRX Oj: Negative-Size memcpy in Oj::Parser create_id Attribute Handling

Summary Oj::Parserparse in usual mode with createid enabled 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 formattr usual.c:63 converts the length to -1 before passing it to memcpy. This causes memcpy to...

GHSA-Q2GM-54R6-8FWM Oj: Use-After-Free in Oj::Parser SAJ Callback via Input Mutation

Summary Oj::Parserparse is vulnerable to a heap use-after-free when a SAJ/SAJ2 callback mutates the input JSON string during parsing. The C engine holds a raw const byte pointer into the Ruby string's internal buffer. If a callback e.g. hashstart resizes the string — for example by calling...

Oj: Use-After-Free in Oj::Parser SAJ Callback via Input Mutation

Summary Oj::Parserparse is vulnerable to a heap use-after-free when a SAJ/SAJ2 callback mutates the input JSON string during parsing. The C engine holds a raw const byte pointer into the Ruby string's internal buffer. If a callback e.g. hashstart resizes the string — for example by calling...

GHSA-9PPP-W3G4-FH4Q Oj: Use-After-Free in Oj::Doc Iterators via Reentrant Close

Summary Oj::Doc iterators eachvalue, eachchild, eachleaf are vulnerable to a heap use-after-free. When a Ruby block yielded during iteration calls doc.close or d.close, the document's heap memory is freed while the C iterator is still running. When control returns from the block, the iterator rea...

Oj: Heap Buffer Overflow in Oj.dump Exception Serialization via Large Indent

Summary Oj.dump in object mode 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...

GHSA-35W3-PJM6-WJ95 Oj: Heap Buffer Overflow in Oj.dump Exception Serialization via Large Indent

Summary Oj.dump in object mode 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...

PT-2026-51083

Name of the Vulnerable Software and Affected Versions Oj versions prior to 3.17.2 Description Oj::Doc iterators each value, each child, each leaf are subject to a heap use-after-free. This occurs when a Ruby block yielded during iteration calls doc.close or d.close, causing the document's heap...