What’s Vulnerable › Vulnerabilities

CVE-2020-25739

• Severity: medium (CVSS 6.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2020-09-23 · updated 2026-06-17
• Weakness: CWE-79

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.

Affected products

• Canonical Ubuntu Linux: 18.04
• Debian Linux: 9.0
• Gon Project Gon: before 6.4.0 — fixed in 6.4.0

How to fix

Upgrade to a fixed version: Gon Project Gon 6.4.0. Check the vendor advisory for mitigations.

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/
• 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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