mod_auth_mellon: open redirect in logout url when using URLs with backslashes
Published Mar 27, 2019
6.1
MEDIUMCVSS 3.0
EPSS 2.12%
Description
A vulnerability was found in mod_auth_mellon before v0.14.2. An open redirect in the logout URL allows requests with backslashes to pass through by assuming that it is a relative URL, while the browsers silently convert backslash characters into forward slashes treating them as an absolute URL. This mismatch allows an attacker to bypass the redirect URL validation logic in apr_uri_parse function.
Affected products
-
- Version v0.14.2StatusaffectedConstraints-
- Version
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Uninett | Mod Auth Mellon | n/a |
|
Configuration 1
- < 0.14.2
Configuration 2
- 29
Configuration 3
- 7.0
Configuration 4
- 18.04
- 18.10
No data.
Red Hat Enterprise Linux 7
mod_auth_mellon-0:0.14.0-2.el7_6.4
Fixed · RHSA-2019:0766
Red Hat Enterprise Linux 8
mod_auth_mellon-0:0.14.0-9.el8
Fixed · RHSA-2019:3421
Red Hat Enterprise Linux 6
mod_auth_mellon
Will not fix
Red Hat Software Collections
httpd24-mod_auth_mellon
Will not fix
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 7 | mod_auth_mellon-0:0.14.0-2.el7_6.4 | Fixed | RHSA-2019:0766 |
| Red Hat Enterprise Linux 8 | mod_auth_mellon-0:0.14.0-9.el8 | Fixed | RHSA-2019:3421 |
| Red Hat Enterprise Linux 6 | mod_auth_mellon | Will not fix | n/a |
| Red Hat Software Collections | httpd24-mod_auth_mellon | Will not fix | n/a |
No package ranges for this CVE.
Remediation
No remediation recorded yet.
Metrics
No CVSS v4.0 score for this CVE.
No CVSS v3.1 score for this CVE.
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
1 other source (Red Hat) ▾
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
AV:N/AC:M/Au:N/C:N/I:P/A:N
This CVE is not in the KEV list.
No CISA SSVC assessment for this CVE yet.
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 2, 2026.
Score over time
2021–2026- EPSS v1
- EPSS v5
- EPSS v2
- EPSS v3
- EPSS v4
Percentile over time
- EPSS v1
- EPSS v5
- EPSS v2
- EPSS v3
- EPSS v4
Table of values (13 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 2, 2026 | 2.12% (0.02121) | 81.22th | v5 (v2026.06.15) |
| Jun 15, 2026 | 2.13% (0.02131) | 79.50th | v5 (v2026.06.15) |
| Mar 17, 2025 | 0.17% (0.00169) | 35.55th | v4 (v2025.03.14) |
| Dec 12, 2024 | 0.27% (0.00272) | 68.81th | v3 (v2023.03.01) |
| Mar 20, 2024 | 0.19% (0.00191) | 55.75th | v3 (v2023.03.01) |
| Mar 7, 2023 | 0.12% (0.00119) | 44.35th | v3 (v2023.03.01) |
| Mar 6, 2023 | 1.18% (0.01183) | 61.76th | v2 (v2022.01.01) |
| Apr 1, 2022 | 1.18% (0.01183) | 58.77th | v2 (v2022.01.01) |
| Feb 4, 2022 | 22.40% (0.22399) | 94.37th | v2 (v2022.01.01) |
| Feb 3, 2022 | 8.31% (0.08307) | 85.36th | v1 |
| Jan 6, 2022 | 8.31% (0.08307) | 85.19th | v1 |
| Jan 5, 2022 | 1.98% (0.01979) | 77.48th | v5 (v2026.06.15) |
| Apr 14, 2021 | 1.98% (0.01979) | 0.00th | v1 |
References (12)
- https://access.redhat.com/errata/RHSA-2019:0766 vendor-advisoryx_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2019:3421 vendor-advisoryx_refsource_REDHAT
- https://access.redhat.com/security/cve/CVE-2019-3877 Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=1691125 Issue Tracking
- https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2019-3877 x_refsource_CONFIRMIssue TrackingPatchThird Party Advisory
- https://github.com/Uninett/mod_auth_mellon/commit/62041428a32de402e0be6ba45fe12df6a83bedb8 x_refsource_CONFIRMPatchThird Party Advisory
- https://github.com/Uninett/mod_auth_mellon/issues/35 x_refsource_CONFIRMPatchThird Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CNW5YMC5TLWVWNJEY6AIWNSNPRAMWPQJ/ vendor-advisoryx_refsource_FEDORA
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/X7NLAU7KROWNTHAYSA2S67X347F42L2I/ vendor-advisoryx_refsource_FEDORA
- https://nvd.nist.gov/vuln/detail/CVE-2019-3877
- https://usn.ubuntu.com/3924-1/ vendor-advisoryx_refsource_UBUNTUThird Party Advisory
- https://www.cve.org/CVERecord?id=CVE-2019-3877
Change history (4)
- MITRE
- CVSS vector changed from CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N to
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N → CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
- CVSS score changed from 6.1 to
5.8 6.1 → 5.8
- CVSS vector changed from CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N to
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
- REDHAT
- CVSS vector changed from CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N to
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N → CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
- CVSS score changed from 5.8 to
6.1 5.8 → 6.1
- CVSS vector changed from CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N to
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N