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CVE-2019-3877

22
FAUCET Score

CVE-2019-3877 describes an open redirect vulnerability in mod_auth_mellon versions prior to 0.14.2, affecting products from Canonical, Fedora Project, and Red Hat. This flaw allows an attacker to bypass redirect URL validation by using backslashes, which browsers interpret as forward slashes, leading to an absolute URL. Rated Medium (CVSS 6.1), the vulnerability requires user interaction (UI:R) and could result in low confidentiality and integrity impacts (C:L/I:L). There is currently no evidence of active exploitation, public exploit code, or significant community discussion surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
< 0.14.2CPE matchmatch criteria
cpe:2.3:a:mod_auth_mellon_project:mod_auth_mellon:*:*:*:*:*:apache:*:*
29CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:29:*:*:*:*:*:*:*
7.0CPE matchmatch criteria
cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*
18.04CPE matchmatch criteria
cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:*
18.10CPE matchmatch criteria
cpe:2.3:o:canonical:ubuntu_linux:18.10:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.0

5.8MEDIUM

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
CHANGED
Confidentiality Impact
NONE
Integrity Impact
LOW
Availability Impact
NONE
Exploitability Score
3.9
Impact Score
1.4
CvssVersion
3.0

Exploit Intelligence

EPSS Score
2.13%
Probability of exploitation in next 30 days
EPSS Percentile
80.0%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0213 is in the 90th percentile among its peer group of 26,234 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.1 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (6)

github_advisorypatch availablevia nvd_reference
View patch
redhatpatch availablevia nvd_reference
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: mod_auth_mellon-0:0.14.0-2.el7_6.4
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: mod_auth_mellon-0:0.14.0-9.el8
View patch
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 6Fixed in: mod_auth_mellon
redhatend of lifevia redhat_api
Product: Red Hat Software CollectionsFixed in: httpd24-mod_auth_mellon

Vendor Advisories (1)

redhatCVE-2019-3877Moderate

mod_auth_mellon: open redirect in logout url when using URLs with backslashes

Mar 22, 2019

References

access.redhat.com / errata/RHSA-2019:0766
access.redhat.com / errata/RHSA-2019:3421
bugzilla.redhat.com / show_bug.cgi
Issue TrackingPatchThird Party Advisory
github.com / Uninett/mod_auth_mellon/commit/62041428a32de402e0be6ba45fe12df6a83bedb8
PatchThird Party Advisory
github.com / Uninett/mod_auth_mellon/issues/35
PatchThird Party Advisory
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/CNW5YMC5TLWVWNJEY6AIWNSNPRAMWPQJ
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/X7NLAU7KROWNTHAYSA2S67X347F42L2I
usn.ubuntu.com / 3924-1
Third Party Advisory