CVE-2025-27788: Ruby JSON Parser has Out-of-bounds Read

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.7% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-03-12 · updated 2026-06-17
Weakness: CWE-125

Description

JSON is a JSON implementation for Ruby. Starting in version 2.10.0 and prior to version 2.10.2, a specially crafted document could cause an out of bound read, most likely resulting in a crash. Versions prior to 2.10.0 are not vulnerable. Version 2.10.2 fixes the problem. No known workarounds are available.

Affected products

ruby-lang Javascript Object Notation: from 2.10.0 before 2.10.2 — fixed in 2.10.2

How to fix

Upgrade to a fixed version: ruby-lang Javascript Object Notation 2.10.2. Check the vendor advisory for mitigations.

References

https://github.com/ruby/json/commit/c56db31f800d5d508389793e69682f99749dbadf
https://github.com/ruby/json/releases/tag/v2.10.2
https://github.com/ruby/json/security/advisories/GHSA-9m3q-rhmv-5q44

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