CVE-2026-54901

A vulnerability in the Oj (Optimized JSON) library for Ruby prior to version 3.17.2 causes heap corruption when parsing a JSON string longer than 2 GB. An integer overflow in the buf_append_string function leads to copying an astronomically large amount of data out of bounds.

The Oj (Optimized JSON) library for Ruby prior to version 3.17.2 has a Use-After-Free vulnerability in SAJ mode. The Oj::Parser does not protect cached object keys (≥35 bytes) from garbage collection, and a Ruby callback in hash_end can free the key memory while the C parser still holds a pointer. This causes a segfault, confirmed by RIP pointing to address 0x4242.

In the Oj (Optimized JSON) library for Ruby, a heap corruption vulnerability exists. When a JSON object key is exactly 65,535 bytes long, an integer truncation in the form_attr function causes a negative length to be passed to memcpy, copying a huge amount of data and crashing the process. The issue is fixed in version 3.17.2.

A use-after-free vulnerability has been discovered in the Oj (Optimized JSON) library for Ruby. Disabling symbol_keys on a reused Oj::Parser instance frees the internal key cache without clearing the pointer, leading to reading from freed memory during subsequent parsing.

A heap use-after-free vulnerability exists in the C engine of the Oj (Optimized JSON) Ruby gem prior to version 3.17.2. The issue occurs when a SAJ/SAJ2 callback mutates the input JSON string during parsing, causing the internal buffer to be reallocated and leaving a dangling pointer.

Oj (Optimized JSON) is a JSON parser and Object marshaller packaged as a Ruby gem. Prior to version 3.17.2, Oj::Doc iterators (each_value, each_child, each_leaf) were 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 reads from the freed region, producing a use-after-free accessible from pure Ruby.

A heap buffer overflow vulnerability was found in the Oj (Optimized JSON) library for Ruby when serializing Exception objects with a large :indent value. The issue affects versions prior to 3.17.2 and has been fixed in that version.

A denial-of-service (DoS) vulnerability was found in the Oj (Optimized JSON) library for Ruby. The Oj::Doc#each_child function, when recursively processing a deeply nested JSON document, overflows a fixed-size stack buffer, causing a process crash. The issue has been fixed in version 3.17.3.

A stack-based buffer overflow vulnerability was found in the Oj (Optimized JSON) library for Ruby in the Oj.dump method. The issue occurs when a large :indent value is provided, causing a 2 GB write to the stack and process crash.

In the Oj (Optimized JSON) library for Ruby, a vulnerability was found where uninitialized stack memory is read when parsing JSON keys of 254 bytes or longer in :object mode. The flaw occurs in form_attr() which passes a stack buffer instead of a properly allocated heap buffer to rb_intern3(), causing process stack memory disclosure. The issue is fixed in version 3.17.3.