Auth bypass in Mod Auth Mellon Project

CVE-2019-3878

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.

EPSS: 0.030 (85.8th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 8.1 (High). Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2019-3878?
CVE-2019-3878 is a high-severity vulnerability in Mod Auth Mellon Project, classified under Authentication Bypass by Primary Weakness. CVSS score: 8.1/10. Published 2019-03-26.
How severe is CVE-2019-3878?
High severity. CVSS v3 base score is 8.1 out of 10.
Is CVE-2019-3878 known to be exploited?
1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.