CVE-2026-54696
LowCVSS 3.7Exploitation Probability (EPSS)
Low risk22th percentile — higher than 22% of all known CVEs
Summary
A heap buffer overflow vulnerability in Ruby JSON versions 2.9.0 through 2.19.8 occurs when generating JSON for an oversized streamed object. An attacker can provide a controlled string near 16 KB, causing writes past the internal JSON generator buffer.
Risk Assessment
Exploitation results in a reliable process crash/denial of service, potentially disrupting Ruby applications using JSON::State#generate or JSON.dump with streaming to IO.
Recommendation
Immediately update the Ruby JSON library to version 2.19.9 or later, which contains the fix for this vulnerability.
Original NVD description (English source)
Ruby JSON is a JSON implementation for Ruby. Versions 2.9.0 through 2.19.8 are vulnerable to heap buffer overflow when the JSON generator is provided with an oversized streamed object. When streaming to an IO JSON.dump(obj, io) and JSON::State#generate(obj, io) can write past the internal JSON generator buffer when a streamed object contains an attacker-controlled string near 16 KB. Exploitation would result in a reliable process crash/denial of service. This issue has been fixed in version 2.19.9.