CVE-2026-54696

LOW

Ruby JSON: JSON generator heap buffer overflow when streaming to an IO

Title source: cna
STIX 2.1

Description

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.

References (2)

Core 2
Core References
X_Refsource_Misc x_refsource_misc
https://github.com/ruby/json/releases/tag/v2.19.9

Scores

CVSS v3 3.7
EPSS 0.0030
EPSS Percentile 22.5%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L

CISA SSVC

Vulnrichment
Exploitation poc
Automatable no
Technical Impact partial

Details

CWE
CWE-122 CWE-131 CWE-787
Status published
Products (2)
ruby/json >= 2.9.0, < 2.19.9
rubygems/json 2.9.0 - 2.19.9RubyGems
Published Jun 30, 2026
Tracked Since Jul 01, 2026