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Public proof of conceptFix available

CVE-2026-44431

A public proof of concept exists; no exploitation attested.

  • Published2026-05-13
  • Fixed in2.7.0
  • WeaknessCWE-200

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

urllib3 is an HTTP client library for Python. From 1.23 to before 2.7.0, cross-origin redirects followed from the low-level API via ProxyManager.connection_from_url().urlopen(..., assert_same_host=False) still forward these sensitive headers. This vulnerability is fixed in 2.7.0.

Timeline

dates in UTC
  1. 2026-05-1316:16CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-44431?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-44431?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD · OSV
Python urllib3
BranchAffectedFixed in
2.7≥ 1.23, < 2.7.02.7.0

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • fence-agents-apcAlmaLinux:8all versions · fixed in 4.2.1-129.el8_10.28and 47 other packages
  • python3-urllib3AlmaLinux:10all versions · fixed in 1.26.19-4.el10_2
  • python3-urllib3AlmaLinux:9all versions · fixed in 1.26.5-8.el9_8
  • python3-urllib3AlmaLinux:8all versions · fixed in 1.24.2-10.el8_10
  • python3.12-urllib3AlmaLinux:9all versions · fixed in 1.26.19-3.el9_8
  • python3.12-urllib3AlmaLinux:8all versions · fixed in 1.26.19-3.el8_10
  • python3.14-urllib3AlmaLinux:10all versions · fixed in 2.6.3-2.el10_2
  • python3.14-urllib3AlmaLinux:9all versions · fixed in 2.6.3-2.el9_8

1 more package range on OSV.dev

Vendor advisories

  • CVE-2026-44431 Red Hat Product Security868 products fixed · 37 known affected

    urllib3: urllib3: Information disclosure via cross-origin redirects forwarding sensitive headers

    exploit-intelligence-tech-preview/vulnerability-analysis-rhel9 as a component of Exploit Intelligence · rhmtc/openshift-migration-rhel8-operator as a component of Migration Toolkit for Containers · migration-toolkit-virtualization/mtv-rhel9-operator as a component of Migration Toolkit for Virtualization · +34 more

  • RHSA-2026:87410 Red Hat Product Security16 products fixed

    Red Hat Security Advisory: RHOAI 2.25.12 - Red Hat OpenShift AI

  • RHSA-2026:83703 Red Hat Product Security4 products fixed

    Red Hat Security Advisory: OpenShift Container Platform 4.21.39 security and extras update

  • RHSA-2026:82415 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: Red Hat AI Inference 3.5.2 (cpu)

  • RHSA-2026:82371 Red Hat Product Security3 products fixed

    Red Hat Security Advisory: Red Hat AI Inference 3.5.2 (spyre)

  • RHSA-2026:82368 Red Hat Product Security2 products fixed

    Red Hat Security Advisory: Red Hat AI Inference 3.5.2 (cuda)

79 more advisories

Full record on NVD

Fix

  1. Update Python urllib3 to 2.7.0
  2. Vendor fix Red Hat Product Security RHSA-2026:87410 · 16 productsFor Red Hat OpenShift AI 2.25.12 see the following documentation, which will be updated shortly for this release, for important instructions on how to upgrade your cluster and fully apply this errata update: https://docs.redhat.com/en/documentation/red_hat_openshift_ai/
  3. Vendor fix Red Hat Product Security RHSA-2026:83703 · 4 productsSee the following documentation, which will be updated shortly for this release, for important instructions on how to upgrade your cluster and fully apply this asynchronous errata update: https://docs.redhat.com/en/documentation/openshift_container_platform/4.21/html/release_notes/ Details on how…
  4. Vendor fix Red Hat Product Security RHSA-2026:82415 · 1 productFor more information visit https://access.redhat.com/errata/RHSA-2026:82415
  5. Vendor fix Red Hat Product Security RHSA-2026:82371 · 3 productsFor more information visit https://access.redhat.com/errata/RHSA-2026:82371
  6. Vendor fix Red Hat Product Security RHSA-2026:82368 · 2 productsFor more information visit https://access.redhat.com/errata/RHSA-2026:82368
  7. Vendor fix Red Hat Product Security RHSA-2026:82066 · 2 productsFor more information visit https://access.redhat.com/errata/RHSA-2026:82066

Advisories and patches

Detection

read 2026-10-23 19:25 UTC
Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
1 repository, unverifiedSSH-PuR66/cve-replay
PoC-in-GitHub

Sources

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
CVSS 4.0 vector
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Published
2026-05-13
Last Modified
2026-06-26
NVD status
Modified
MSRC Title
urllib3: Sensitive headers forwarded across origins in proxied low-level redirects

Frequently asked questions

What is CVE-2026-44431?

urllib3 is an HTTP client library for Python. From 1.23 to before 2.7.0, cross-origin redirects followed from the low-level API via ProxyManager.connection_from_url().urlopen(..., assert_same_host=False) still forward these sensitive headers. This vulnerability is fixed in 2.7.0.

Is CVE-2026-44431 actively exploited?

Active exploitation of CVE-2026-44431 has not been confirmed. Its EPSS score was 0.3% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-44431?

CVE-2026-44431 has a CVSS v3 base score of 5.3 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N.

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