CVE-2019-3878: Canonical Ubuntu Linux

High severity, CVSS 8.1. EPSS: 3% chance of exploitation in the next 30 days.

A vulnerability was found in mod_auth_mellon before v0.14.2. If Apache is configured as a reverse proxy and mod_auth_mellon is configured to only let through authenticated users (with the require valid-user directive), adding special HTTP headers that are normally used to start the special SAML ECP (non-browser based) can be used to bypass authentication.

Affected products

• Canonical Ubuntu Linux: version 18.04 only; version 18.10 only
• Fedoraproject Fedora: version 29 only; version 30 only
• Mod Auth Mellon Project Mod Auth Mellon: before 0.14.2 (fixed in 0.14.2)
• Red Hat Enterprise Linux: version 7.0 only
• Red Hat Enterprise Linux Desktop: version 7.0 only
• Red Hat Enterprise Linux Server: version 7.0 only
• Red Hat Enterprise Linux Server Aus: version 7.6 only
• Red Hat Enterprise Linux Server Eus: version 7.6 only
• Red Hat Enterprise Linux Server Tus: version 7.6 only
• Red Hat Enterprise Linux Workstation: version 7.0 only

Published 2019-03-26. Last modified 2026-06-17.