Description
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
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| uninett | mod_auth_mellon | before v0.14.2 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | libapache2-mod-auth-mellon | 0.14.2-1 | — |
| Debian 13 | libapache2-mod-auth-mellon | 0.14.2-1 | — |
| Debian 12 | libapache2-mod-auth-mellon | 0.14.2-1 | — |
| Debian 9 | libapache2-mod-auth-mellon | 0.12.0-2+deb9u1 | DSA-4414-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | libapache2-mod-auth-mellon | 0.14.2-1ubuntu1 | — |
| Ubuntu 18.04 LTS | libapache2-mod-auth-mellon | 0.13.1-1ubuntu0.1 | USN-3924-1 |
| Ubuntu 16.04 LTS | libapache2-mod-auth-mellon | 0.12.0-2+deb9u1build0.16.04.1 | USN-4597-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 8 | mod_auth_mellon | 0.14.0-3.el8_0.2 | RHSA-2019:0985 |
| RHEL 7 | mod_auth_mellon +1 | 0.14.0-2.el7_6.4 | RHSA-2019:0766 |
| RHEL 3 | httpd24-httpd +5 | 2.4.34-7.el6.1 | RHSA-2019:0746 |
| RHEL 3 | httpd24-mod_auth_mellon | 0.13.1-2.el7.1 | RHSA-2019:0746 |
| RHEL 3 | httpd24-mod_md | 2.4.34-7.el7.1 | RHSA-2019:0746 |
| RHEL 3 | httpd24-mod_ssl +1 | 1:2.4.34-7.el6.1 | RHSA-2019:0746 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2 | mod_auth_mellon +1 | 0.14.0-2.amzn2.4 | ALAS2-2019-1200 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 8 | mod_auth_mellon | 0.14.0-3.el8_0.2 | ELSA-2019-0985 |
| Oracle Linux 7 | mod_auth_mellon +1 | 0.14.0-2.el7_6.4 | ELSA-2019-0766 |
Advisories 9
- RHSA-2019:0746 Red Hat Security Advisory: httpd24-httpd and httpd24-mod_auth_mellon security update Red Hat Security Advisories (RHSA) · Sep 21, 2026
- RHSA-2019:0985 Red Hat Security Advisory: mod_auth_mellon security update Red Hat Security Advisories (RHSA) · Jun 29, 2026
- RHSA-2019:0766 Red Hat Security Advisory: mod_auth_mellon security and bug fix update Red Hat Security Advisories (RHSA) · Jun 29, 2026
- DSA-4414-1 libapache2-mod-auth-mellon - security update Debian Security (DSA / DLA) · Mar 9, 2026
- USN-4597-1 libapache2-mod-auth-mellon vulnerabilities Ubuntu Security Notices (USN) · Feb 10, 2026
- USN-3924-1 libapache2-mod-auth-mellon vulnerabilities Ubuntu Security Notices (USN) · Feb 10, 2026
- ELSA-2019-0985 Important: mod_auth_mellon security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Jul 30, 2019
- ALAS2-2019-1200 Important: mod_auth_mellon security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · May 20, 2019
- ELSA-2019-0766 Important: mod_auth_mellon security and bug fix update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Apr 16, 2019
References
- https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2019-3878
- https://github.com/Uninett/mod_auth_mellon/pull/196
- USN-3924-1 vendor-advisory
- FEDORA-2019-db1e9b3002 vendor-advisory
- FEDORA-2019-2d8ee47f61 vendor-advisory
- RHSA-2019:0746 vendor-advisory
- RHSA-2019:0766 vendor-advisory
- RHSA-2019:0985 vendor-advisory
- RHBA-2019:0959 vendor-advisory