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CVE-2018-25091· NVD / CVE Program· CNA mitre

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

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).

MediumCVSS 6.1 · v3.1—No exploit Fix available

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Published
Oct 15, 2023
Updated
Jun 16, 2026
EPSS
0.5% · 42th percentile
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Report tools

JSON

Action score

24

Monitor

Low priority for now.

CVSS
24 / 40 · 6.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.5%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Affected systems

VendorProduct
pythonurllib3

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • python urllib3before 1.24.2

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:10python-urllib3before 1.24.1-1+deb10u11.24.1-1+deb10u1
Debian:12python-urllib3before 1.25.6-41.25.6-4
PyPIurllib3before 1.24.21.24.2
Red Hat:enterprise_linux:8::appstreamaardvark-dnsbefore 2:1.10.0-1.module+el8.10.0+21209+52deeb512:1.10.0-1.module+el8.10.0+21209+52deeb51
Red Hat:enterprise_linux:8::appstreambuildahbefore 2:1.33.6-2.module+el8.10.0+21371+46937ece2:1.33.6-2.module+el8.10.0+21371+46937ece
Red Hat:enterprise_linux:8::appstreambuildah-debuginfobefore 2:1.33.6-2.module+el8.10.0+21371+46937ece2:1.33.6-2.module+el8.10.0+21371+46937ece
Red Hat:enterprise_linux:8::appstreambuildah-debugsourcebefore 2:1.33.6-2.module+el8.10.0+21371+46937ece2:1.33.6-2.module+el8.10.0+21371+46937ece
Red Hat:enterprise_linux:8::appstreambuildah-testsbefore 2:1.33.6-2.module+el8.10.0+21371+46937ece2:1.33.6-2.module+el8.10.0+21371+46937ece
Red Hat:enterprise_linux:8::appstreambuildah-tests-debuginfobefore 2:1.33.6-2.module+el8.10.0+21371+46937ece2:1.33.6-2.module+el8.10.0+21371+46937ece
Red Hat:enterprise_linux:8::appstreamcockpit-podmanbefore 0:84.1-1.module+el8.10.0+21373+0d273fdf0:84.1-1.module+el8.10.0+21373+0d273fdf
Red Hat:enterprise_linux:8::appstreamconmonbefore 3:2.1.10-1.module+el8.10.0+21077+98b84d8a3:2.1.10-1.module+el8.10.0+21077+98b84d8a
Red Hat:enterprise_linux:8::appstreamconmon-debuginfobefore 3:2.1.10-1.module+el8.10.0+21077+98b84d8a3:2.1.10-1.module+el8.10.0+21077+98b84d8a
Red Hat:enterprise_linux:8::appstreamconmon-debugsourcebefore 3:2.1.10-1.module+el8.10.0+21077+98b84d8a3:2.1.10-1.module+el8.10.0+21077+98b84d8a
Red Hat:enterprise_linux:8::appstreamcontainer-selinuxbefore 2:2.229.0-2.module+el8.10.0+21196+3f0abbca2:2.229.0-2.module+el8.10.0+21196+3f0abbca
Red Hat:enterprise_linux:8::appstreamcontainernetworking-pluginsbefore 1:1.4.0-2.module+el8.10.0+21366+f9cb49f81:1.4.0-2.module+el8.10.0+21366+f9cb49f8
Red Hat:enterprise_linux:8::appstreamcontainernetworking-plugins-debuginfobefore 1:1.4.0-2.module+el8.10.0+21366+f9cb49f81:1.4.0-2.module+el8.10.0+21366+f9cb49f8
Red Hat:enterprise_linux:8::appstreamcontainernetworking-plugins-debugsourcebefore 1:1.4.0-2.module+el8.10.0+21366+f9cb49f81:1.4.0-2.module+el8.10.0+21366+f9cb49f8
Red Hat:enterprise_linux:8::appstreamcontainers-commonbefore 2:1-81.module+el8.10.0+21340+c6c7475a2:1-81.module+el8.10.0+21340+c6c7475a
Red Hat:enterprise_linux:8::appstreamcritbefore 0:3.18-4.module+el8.9.0+20326+387084d00:3.18-4.module+el8.9.0+20326+387084d0
Red Hat:enterprise_linux:8::appstreamcriubefore 0:3.18-4.module+el8.9.0+20326+387084d00:3.18-4.module+el8.9.0+20326+387084d0
Red Hat:enterprise_linux:8::appstreamcriu-debuginfobefore 0:3.18-4.module+el8.9.0+20326+387084d00:3.18-4.module+el8.9.0+20326+387084d0
Red Hat:enterprise_linux:8::appstreamcriu-debugsourcebefore 0:3.18-4.module+el8.9.0+20326+387084d00:3.18-4.module+el8.9.0+20326+387084d0
Red Hat:enterprise_linux:8::appstreamcriu-develbefore 0:3.18-4.module+el8.9.0+20326+387084d00:3.18-4.module+el8.9.0+20326+387084d0
Red Hat:enterprise_linux:8::appstreamcriu-libsbefore 0:3.18-4.module+el8.9.0+20326+387084d00:3.18-4.module+el8.9.0+20326+387084d0

+96

Same product

python: all records

Other highest-scoring records for the same primary product.

  • CVE-2018-20060urllib3 before version 1.23 does not remove the Authorization HTTP header when following a cross-origin redirect (i.e., a redirect that diff
    40Plan
  • CVE-2026-21441urllib3 vulnerable to decompression-bomb safeguard bypass when following HTTP redirects (streaming API)
    36Monitor
  • CVE-2026-44432urllib3: Decompression-bomb safeguards bypassed in parts of the streaming API
    35Monitor
  • CVE-2025-66471urllib3 Streaming API improperly handles highly compressed data
    35Monitor
  • CVE-2025-66418urllib3 allows an unbounded number of links in the decompression chain
    35Monitor
  • CVE-2026-44431urllib3: Sensitive headers forwarded across origins in proxied low-level redirects
    32Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
debian:python-urllib31.25.6-4 · Debian:12Package registry (OSV)
PyPI:urllib31.24.2Package registry (OSV)
red hat:aardvark-dns2:1.10.0-1.module+el8.10.0+21209+52deeb51 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:buildah2:1.33.6-2.module+el8.10.0+21371+46937ece · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:buildah-debuginfo2:1.33.6-2.module+el8.10.0+21371+46937ece · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:buildah-debugsource2:1.33.6-2.module+el8.10.0+21371+46937ece · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:buildah-tests2:1.33.6-2.module+el8.10.0+21371+46937ece · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:buildah-tests-debuginfo2:1.33.6-2.module+el8.10.0+21371+46937ece · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:cockpit-podman0:84.1-1.module+el8.10.0+21373+0d273fdf · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:conmon3:2.1.10-1.module+el8.10.0+21077+98b84d8a · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:conmon-debuginfo3:2.1.10-1.module+el8.10.0+21077+98b84d8a · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:conmon-debugsource3:2.1.10-1.module+el8.10.0+21077+98b84d8a · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:container-selinux2:2.229.0-2.module+el8.10.0+21196+3f0abbca · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:containernetworking-plugins1:1.4.0-2.module+el8.10.0+21366+f9cb49f8 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
rocky linux:aardvark-dns2:1.10.0-1.module+el8.10.0+1815+5fe7415e · Rocky Linux:8Package registry (OSV)
rocky linux:cockpit-podman0:84.1-1.module+el8.10.0+1815+5fe7415e · Rocky Linux:8Package registry (OSV)
rocky linux:conmon3:2.1.10-1.module+el8.10.0+1896+b18fa106 · Rocky Linux:8Package registry (OSV)
rocky linux:container-selinux2:2.229.0-2.module+el8.10.0+1815+5fe7415e · Rocky Linux:8Package registry (OSV)
rocky linux:containernetworking-plugins1:1.4.0-2.module+el8.10.0+1815+5fe7415e · Rocky Linux:8Package registry (OSV)
rocky linux:containers-common2:1-81.module+el8.10.0+1815+5fe7415e · Rocky Linux:8Package registry (OSV)
rocky linux:crun0:1.14.3-2.module+el8.10.0+1815+5fe7415e · Rocky Linux:8Package registry (OSV)
rocky linux:fuse-overlayfs0:1.13-1.module+el8.10.0+1815+5fe7415e · Rocky Linux:8Package registry (OSV)
rocky linux:libslirp0:4.4.0-1.module+el8.9.0+1445+07728297 · Rocky Linux:8Package registry (OSV)
rocky linux:netavark2:1.10.3-1.module+el8.10.0+1815+5fe7415e · Rocky Linux:8Package registry (OSV)
rocky linux:oci-seccomp-bpf-hook0:1.2.10-1.module+el8.10.0+1815+5fe7415e · Rocky Linux:8Package registry (OSV)
rocky linux:python-podman0:4.9.0-1.module+el8.10.0+1815+5fe7415e · Rocky Linux:8Package registry (OSV)
suse:python-urllib31.23-3.25.1 · SUSE:OpenStack Cloud 9Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • A user must open a link or visit a page.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
low · data can be read
Integrity
low · data or configuration can be modified
Availability
none

Impact can extend beyond the vulnerable component (scope changes).

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
Required
Scope
Changed
Confidentiality impact
Low
Integrity impact
Low
Availability impact
None

Weakness class (CWE)

CWE-601 · URL Redirection to Untrusted Site ('Open Redirect')

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records