CVE-2026-54696 PUBLISHED

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

Assigner: GitHub_M
Reserved: 15.06.2026 Published: 30.06.2026 Updated: 01.07.2026

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.

Metrics

CVSS Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
CVSS Score: 3.7

Product Status

Vendor ruby
Product json
Versions
  • Version >= 2.9.0, < 2.19.9 is affected

References

Problem Types

  • CWE-122: Heap-based Buffer Overflow CWE
  • CWE-131: Incorrect Calculation of Buffer Size CWE
  • CWE-787: Out-of-bounds Write CWE