RubySec

Providing security resources for the Ruby community

CVE-2026-54502 (oj): Oj - Stack Buffer Overflow in Oj.dump via Large Indent

Oj - Stack Buffer Overflow in Oj.dump via Large Indent

Published: June 19, 2026

SECURITY IDENTIFIERS

GEM

oj

PATCHED VERSIONS

>= 3.17.3

DESCRIPTION

Summary

Oj.dump is vulnerable to a stack-based buffer overflow when a large :indent value is provided by the developer. fill_indent in dump.h calls memset(indent_str, ' ', (size_t)opts->indent) without validating the size. When opts->indent is set to INT_MAX (2,147,483,647), the (size_t) cast preserves the large value and memset writes 2 GB into the stack-allocated out buffer (4,184 bytes), corrupting the stack and crashing the process.

RELATED