CVE-2018-25091

urllib3 before 1.24.2 does not remove the authorization HTTP header when following a cross-origin redirect (i.e., a redirect that differs in host, port, or scheme). This can allow for credentials in the authorization header to be exposed to unintended hosts or transmitted in cleartext. NOTE: this issue exists because of an incomplete fix for CVE-2018-20060 (which was case-sensitive).

Published: 2023-10-15 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2018-25091 is rated Low Risk (38.5/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.51%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2018-25091

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.22% 0.51% +0.29%
2 2026-05-09 0.25% 0.22% -0.03%
3 2025-11-21 — 0.25% —

Full EPSS history (10 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2018-25091

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.1 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 2.8 2.7 [email protected]

Weakness enumeration for CVE-2018-25091

GitHub Security Advisory for CVE-2018-25091

GHSA-gwvm-45gx-3cf8 · Severity: medium · Ecosystem: pip — Authorization Header forwarded on redirect

OS Trackers for CVE-2018-25091

vendor priority summary link
debian not yet assigned CVE-2018-25091 not yet assigned priority: Debian including 1 source packages (python-urllib3), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2018-25091
redhat medium — https://access.redhat.com/security/cve/CVE-2018-25091
suse medium CVE-2018-25091 severity moderate: SUSE including 40 source package names (aardvark-dns-1.10.0-1.module+el8.10.0+21209+52deeb51, buildah-1.33.6-2.module+el8.10.0+21371+46937ece, …), 123 product×package rows across 44 product lines (HPE Helion OpenStack 8, SUSE CaaS Platform 4.0, … (44 product lines)): Known Not Affected 86, Fixed 37. https://www.suse.com/security/cve/CVE-2018-25091/
ubuntu medium CVE-2018-25091 medium priority: Ubuntu including 2 source packages (python-pip, python-urllib3), 24 status rows across 12 suites (bionic, focal, jammy, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): not-affected 15, released 6, needed 2, ignored 1. https://ubuntu.com/security/CVE-2018-25091

Affected software / configurations for CVE-2018-25091

Vendor Product Version Raw CPE
python urllib3 < 1.24.2 cpe:2.3:a:python:urllib3:*:*:*:*:*:*:*:*

References for CVE-2018-25091

cvelogic Threat Intelligence