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NVD / CVE Program· CNA GitHub_M

CVE-2024-37891: Proxy-Authorization request header isn't stripped during cross-origin redirects in urllib3

MediumCVSS 6.5 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 26/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 1.1% (FIRST EPSS); higher than 67.1% of all records.
  • Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Azure Linux 3.0 ARM 2.0.7-1, 24.2-2; Azure Linux 3.0 x64 2.0.7-1, 24.2-2; CBL Mariner 2.0 ARM 1.26.19-1.
  • Severity is disputed: the assigning authority (CNA) scores it 4.4, NVD 6.5.

Low priority for now. Upgrade to Azure Linux 3.0 ARM 2.0.7-1, 24.2-2; Azure Linux 3.0 x64 2.0.7-1, 24.2-2; CBL Mariner 2.0 ARM 1.26.19-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

urllib3 is a user-friendly HTTP client library for Python. When using urllib3's proxy support with `ProxyManager`, the `Proxy-Authorization` header is only sent to the configured proxy, as expected. However, when sending HTTP requests *without* using urllib3's proxy support, it's possible to accidentally configure the `Proxy-Authorization` header even though it won't have any effect as the request is not using a forwarding proxy or a tunneling proxy. In those cases, urllib3 doesn't treat the `Proxy-Authorization` HTTP header as one carrying authentication material and thus doesn't strip the header on cross-origin redirects. Because this is a highly unlikely scenario, we believe the severity of this vulnerability is low for almost all users. Out of an abundance of caution urllib3 will automatically strip the `Proxy-Authorization` header during cross-origin redirects to avoid the small chance that users are doing this on accident. Users should use urllib3's proxy support or disable automatic redirects to achieve safe processing of the `Proxy-Authorization` header, but we still decided to strip the header by default in order to further protect users who aren't using the correct approach. We believe the number of usages affected by this advisory is low. It requires all of the following to be true to be exploited: 1. Setting the `Proxy-Authorization` header without using urllib3's built-in proxy support. 2. Not disabling HTTP redirects. 3. Either not using an HTTPS origin server or for the proxy or target origin to redirect to a malicious origin. Users are advised to update to either version 1.26.19 or version 2.2.2. Users unable to upgrade may use the `Proxy-Authorization` header with urllib3's `ProxyManager`, disable HTTP redirects using `redirects=False` when sending requests, or not user the `Proxy-Authorization` header as mitigations.

Published
Jun 17, 2024
Updated
Jun 17, 2026
EPSS
1.1% · 67th percentile

Report tools

JSON

Action score

26

Monitor

Low priority for now.

CVSS
26 / 40 · 6.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 1.1%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
6.5
CNA · GitHub_M
4.4
2.1 point gap

CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:N/A:N

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
pythonurllib3
debiandebian linux
netappactive iq unified manager

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • urllib3 urllib3

    • < 1.26.19, >= 2.0.0, < 2.2.2affected
Affected versions · NVD (4)

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

  • debian debian linux11.0
  • netapp active iq unified managerall versions
  • python urllib3before 1.26.19
  • python urllib32.0.0 and later · before 2.2.2

Package-level exposure

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

EcosystemPackageAffected rangeFix
AlmaLinux:8aardvark-dnsbefore 2:1.10.0-1.module_el8.10.0+3792+03eaed9c2:1.10.0-1.module_el8.10.0+3792+03eaed9c
AlmaLinux:8aardvark-dnsbefore 2:1.10.0-1.module_el8.10.0+3858+6ad51f9f2:1.10.0-1.module_el8.10.0+3858+6ad51f9f
AlmaLinux:8aardvark-dnsbefore 2:1.10.0-1.module_el8.10.0+3876+e55593a82:1.10.0-1.module_el8.10.0+3876+e55593a8
AlmaLinux:8buildahbefore 2:1.33.8-4.module_el8.10.0+3876+e55593a82:1.33.8-4.module_el8.10.0+3876+e55593a8
AlmaLinux:8buildah-testsbefore 2:1.33.8-4.module_el8.10.0+3876+e55593a82:1.33.8-4.module_el8.10.0+3876+e55593a8
AlmaLinux:8cockpit-podmanbefore 84.1-1.module_el8.10.0+3858+6ad51f9f84.1-1.module_el8.10.0+3858+6ad51f9f
AlmaLinux:8conmonbefore 3:2.1.10-1.module_el8.10.0+3845+87b845523:2.1.10-1.module_el8.10.0+3845+87b84552
AlmaLinux:8conmonbefore 3:2.1.10-1.module_el8.10.0+3876+e55593a83:2.1.10-1.module_el8.10.0+3876+e55593a8
AlmaLinux:8conmonbefore 3:2.1.10-1.module_el8.10.0+3858+6ad51f9f3:2.1.10-1.module_el8.10.0+3858+6ad51f9f
AlmaLinux:8container-selinuxbefore 2:2.229.0-2.module_el8.10.0+3876+e55593a82:2.229.0-2.module_el8.10.0+3876+e55593a8
AlmaLinux:8containernetworking-pluginsbefore 1:1.4.0-5.module_el8.10.0+3876+e55593a81:1.4.0-5.module_el8.10.0+3876+e55593a8
AlmaLinux:8containers-commonbefore 2:1-82.module_el8.10.0+3876+e55593a82:1-82.module_el8.10.0+3876+e55593a8
AlmaLinux:8critbefore 3.18-5.module_el8.10.0+3858+6ad51f9f3.18-5.module_el8.10.0+3858+6ad51f9f
AlmaLinux:8critbefore 3.18-5.module_el8.10.0+3845+87b845523.18-5.module_el8.10.0+3845+87b84552
AlmaLinux:8criubefore 3.18-5.module_el8.10.0+3876+e55593a83.18-5.module_el8.10.0+3876+e55593a8
AlmaLinux:8criubefore 3.18-5.module_el8.10.0+3845+87b845523.18-5.module_el8.10.0+3845+87b84552
AlmaLinux:8criu-develbefore 3.18-5.module_el8.10.0+3858+6ad51f9f3.18-5.module_el8.10.0+3858+6ad51f9f
AlmaLinux:8criu-develbefore 3.18-5.module_el8.10.0+3876+e55593a83.18-5.module_el8.10.0+3876+e55593a8
AlmaLinux:8criu-libsbefore 3.18-5.module_el8.10.0+3876+e55593a83.18-5.module_el8.10.0+3876+e55593a8
AlmaLinux:8criu-libsbefore 3.18-5.module_el8.10.0+3845+87b845523.18-5.module_el8.10.0+3845+87b84552
AlmaLinux:8crunbefore 1.14.3-2.module_el8.10.0+3858+6ad51f9f1.14.3-2.module_el8.10.0+3858+6ad51f9f
AlmaLinux:8crunbefore 1.14.3-2.module_el8.10.0+3876+e55593a81.14.3-2.module_el8.10.0+3876+e55593a8
AlmaLinux:8fence-agents-aliyunbefore 4.2.1-129.el8_10.44.2.1-129.el8_10.4
AlmaLinux:8fence-agents-allbefore 4.2.1-129.el8_10.44.2.1-129.el8_10.4

+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…
    40Plan
  • CVE-2026-21441urllib3 vulnerable to decompression-bomb safeguard bypass when following HTTP redirects (streaming API)
    36Monitor
  • CVE-2026-97689urllib3: HTTPResponse.stream()/read_chunked() buffers an unbounded chunk-size line into memory
    35Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2018-25091Oct 15, 2023 · urllib3 before 1.24.2 does not remove the authorization HTTP header when following a cross-origin redirect (i.e., a redirect that differs…
    24Monitor
  • ← EarlierCVE-2023-45803Oct 17, 2023 · Request body not stripped after redirect in urllib3
    16Monitor
  • Later →CVE-2025-50181Jun 18, 2025 · urllib3 redirects are not disabled when retries are disabled on PoolManager instantiation
    24Monitor

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
Azure Linux 3.0 ARM2.0.7-1 · python-urllib3Microsoft (MSRC)
Azure Linux 3.0 ARM24.2-2 · python-pipMicrosoft (MSRC)
Azure Linux 3.0 x642.0.7-1 · python-urllib3Microsoft (MSRC)
Azure Linux 3.0 x6424.2-2 · python-pipMicrosoft (MSRC)
CBL Mariner 2.0 ARM1.26.19-1 · python-urllib3Microsoft (MSRC)
CBL Mariner 2.0 x641.26.19-1 · python-urllib3Microsoft (MSRC)
almalinux:fence-agents-aliyun4.10.0-62.el9_4.4.alma.1 · AlmaLinux:9Package registry (OSV)
almalinux:fence-agents-all4.10.0-62.el9_4.4.alma.1 · AlmaLinux:9Package registry (OSV)
almalinux:fence-agents-amt-ws4.10.0-62.el9_4.4.alma.1 · AlmaLinux:9Package registry (OSV)
almalinux:fence-agents-apc4.10.0-62.el9_4.4.alma.1 · AlmaLinux:9Package registry (OSV)
almalinux:fence-agents-apc-snmp4.10.0-62.el9_4.4.alma.1 · AlmaLinux:9Package registry (OSV)
almalinux:fence-agents-aws4.10.0-62.el9_4.4.alma.1 · AlmaLinux:9Package registry (OSV)
almalinux:fence-agents-azure-arm4.10.0-62.el9_4.4.alma.1 · AlmaLinux:9Package registry (OSV)
almalinux:fence-agents-bladecenter4.10.0-62.el9_4.4.alma.1 · AlmaLinux:9Package registry (OSV)
almalinux:fence-agents-brocade4.10.0-62.el9_4.4.alma.1 · AlmaLinux:9Package registry (OSV)
almalinux:fence-agents-cisco-mds4.10.0-62.el9_4.4.alma.1 · AlmaLinux:9Package registry (OSV)
almalinux:fence-agents-cisco-ucs4.10.0-62.el9_4.4.alma.1 · AlmaLinux:9Package registry (OSV)
almalinux:fence-agents-common4.10.0-62.el9_4.4.alma.1 · AlmaLinux:9Package registry (OSV)
debian:python-urllib31.26.12-1+deb12u1 · Debian:12Package registry (OSV)
opensuse:oci-cli3.76.2-1.1 · openSUSE:TumbleweedPackage registry (OSV)
opensuse:python-urllib32.0.7-150400.7.18.1 · openSUSE:Leap 15.5Package registry (OSV)
opensuse:python-urllib3_11.26.18-150600.3.3.1 · openSUSE:Leap 15.6Package registry (OSV)
PyPI:urllib31.26.19Package registry (OSV)
PyPI:urllib32.2.2Package registry (OSV)
red hat:fence-agents0:4.10.0-62.el9_4.4 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:fence-agents-common0:4.10.0-62.el9_4.4 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:fence-agents-compute0:4.10.0-62.el9_4.4 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:fence-agents-debuginfo0:4.10.0-62.el9_4.4 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:fence-agents-debugsource0:4.10.0-62.el9_4.4 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:fence-agents-ibm-powervs0:4.10.0-62.el9_4.4 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)

+24

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.

Patch and commit links

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

Not on record for this CVE: EPSS history · researcher credit · variant or chain candidate · public bounty program.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
none
Availability
none
Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
None
Availability impact
None

Weakness class (CWE)

CWE-669 · Incorrect Resource Transfer Between Spheres

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/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.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

References

Show all references (3 more)

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

All records