CVE-2025-12790: MQTT does not validate hostnames

November 6, 2025

A flaw was found in Rubygem MQTT. By default, the package used to not have hostname validation, resulting in possible Man-in-the-Middle (MITM) attack.

References

access.redhat.com/security/cve/CVE-2025-12790
bugzilla.redhat.com/show_bug.cgi?id=2413004
github.com/advisories/GHSA-9c5q-w6gr-fxcq
github.com/njh/ruby-mqtt/blob/main/NEWS.md
nvd.nist.gov/vuln/detail/CVE-2025-12790

Code Behaviors & Features

Detect and mitigate CVE-2025-12790 with GitLab Dependency Scanning

Secure your software supply chain by verifying that all open source dependencies used in your projects contain no disclosed vulnerabilities. Dependency Scanning using SBOM also detects vulnerabilities from proprietary advisories that this site does not include. Learn more about Dependency Scanning using SBOM →