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HIGH

CVE-2019-3878

CVSS v3

8.1

HIGH

EPSS Score

3.0 %

exploit probability, as of 2026-10-19

CISA KEV

No

known exploited

Exploitation

—

SSVC status

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Affected and fixed versions

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Vendor advisories

  • CVE-2019-3878 Red Hat Product Security241 products fixed

    mod_auth_mellon: authentication bypass in ECP flow

  • RHSA-2019:0985 Red Hat Product Security17 products fixed

    Red Hat Security Advisory: mod_auth_mellon security update

  • RHSA-2019:0766 Red Hat Product Security35 products fixed

    Red Hat Security Advisory: mod_auth_mellon security and bug fix update

  • RHSA-2019:0746 Red Hat Product Security189 products fixed

    Red Hat Security Advisory: httpd24-httpd and httpd24-mod_auth_mellon security update

Full record on NVD

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.

Technical details

Published
2019-03-26

Frequently asked questions

What is 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.

Is CVE-2019-3878 actively exploited?

Active exploitation of CVE-2019-3878 has not been confirmed. Its EPSS score was 3.0% on 2026-10-19, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2019-3878?

CVE-2019-3878 has a CVSS v3 base score of 8.1 (HIGH severity).

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