vulnerability

Ubuntu: (Multiple Advisories) (CVE-2024-45614): Puma vulnerability

Severity
6
CVSS
(AV:N/AC:M/Au:N/C:P/I:P/A:N)
Published
Sep 19, 2024
Added
Sep 25, 2024
Modified
Apr 16, 2026

Description

Puma is a Ruby/Rack web server built for parallelism. In affected versions clients could clobber values set by intermediate proxies (such as X-Forwarded-For) by providing a underscore version of the same header (X-Forwarded_For). Any users relying on proxy set variables is affected. v6.4.3/v5.6.9 now discards any headers using underscores if the non-underscore version also exists. Effectively, allowing the proxy defined headers to always win. Users are advised to upgrade. Nginx has a underscores_in_headers configuration variable to discard these headers at the proxy level as a mitigation. Any users that are implicitly trusting the proxy defined headers for security should immediately cease doing so until upgraded to the fixed versions.

Solutions

ubuntu-pro-upgrade-pumaubuntu-upgrade-puma
Title
Rapid7 Labs

2026 Global Threat Landscape Report

The predictive window has collapsed. Exploitation follows disclosure in days. See how attackers are accelerating and how to stay ahead.