CVE-2026-54502CWE-121

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

Medium · published June 30, 2026

CVSS v4.0
6.3
EPSS
0%
Percentile
26.0
In the wild
Unconfirmed
What it is

Oj (Optimized JSON) is a JSON parser and Object marshaller packaged as a Ruby gem. In versions prior to 3.17.2, 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. This issue has been fixed in version 3.17.2.

The record
Technical detail
CVSS v4.0
6.3 · MEDIUM
Vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
EPSS
0.00338 · 26.0th percentile
Weakness
CWE-121 · Stack-based Buffer Overflow
Published
2026-06-30T23:10Z
EPSS history
Timeline
  • 30 JUN 23:10Z
    Oj: Stack Buffer Overflow in Oj.dump via Large Indent
    cvelistv5