CVE-2026-21441

Highest-risk unexploited with PoCs

Exploit code exists, no confirmed in-the-wild activity, ranked by EPSS

Actively Exploited

Confirmed exploited in the wild, sorted by most recently updated

CVSS 8.9EPSS 3%

Published 2026-01-07Updated 2026-01-07

Vulnerability details

urllib3 is an HTTP client library for Python. urllib3's streaming API is designed for the efficient handling of large HTTP responses by reading the content in chunks, rather than loading the entire response body into memory at once. urllib3 can perform decoding or decompression based on the HTTP `Content-Encoding` header (e.g., `gzip`, `deflate`, `br`, or `zstd`). When using the streaming API, the library decompresses only the necessary bytes, enabling partial content consumption. Starting in version 1.22 and prior to version 2.6.3, for HTTP redirect responses, the library would read the entire response body to drain the connection and decompress the content unnecessarily. This decompression occurred even before any read methods were called, and configured read limits did not restrict the amount of decompressed data. As a result, there was no safeguard against decompression bombs. A malicious server could exploit this to trigger excessive resource consumption on the client. Applications and libraries are affected when they stream content from untrusted sources by setting `preload_content=False` when they do not disable redirects. Users should upgrade to at least urllib3 v2.6.3, in which the library does not decode content of redirect responses when `preload_content=False`. If upgrading is not immediately possible, disable redirects by setting `redirect=False` for requests to untrusted source.

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H

CNAGitHub_M

EPSS score history

Sources

3 links

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CVE Organization RedHat Vuln DB NVD Analysis

Profile

CVSS

8.9

EPSS

Published

2026-01-07

Updated

2026-01-07

CNA

GitHub_M

Vendors

urllib3

1 product

CPEs

170

cpe:/o:redhat:enterprise_linux:7::server

cpe:/a:redhat:openstack:17.1

cpe:/a:redhat:openstack:17.1::el8

cpe:/a:redhat:rhui:4::el8

cpe:/a:redhat:satellite:6.16::el8

cpe:/a:redhat:satellite_capsule:6.16::el8

cpe:/a:redhat:satellite_utils:6.16::el8

cpe:/a:redhat:satellite:6.16::el9

cpe:/a:redhat:satellite_capsule:6.16::el9

cpe:/a:redhat:satellite_utils:6.16::el9

cpe:/a:redhat:satellite:6.17::el9

cpe:/a:redhat:satellite_capsule:6.17::el9

cpe:/a:redhat:satellite_utils:6.17::el9

cpe:/a:redhat:satellite:6.18::el9

cpe:/a:redhat:satellite_capsule:6.18::el9

cpe:/a:redhat:satellite_maintenance:6.18::el9

cpe:/a:redhat:satellite_utils:6.18::el9

cpe:/a:redhat:enterprise_linux:8::appstream

cpe:/a:redhat:rhel_aus:8.4::appstream

cpe:/a:redhat:rhel_eus_long_life:8.4::appstream

cpe:/a:redhat:rhel_aus:8.6::appstream

cpe:/a:redhat:rhel_e4s:8.6::appstream

cpe:/a:redhat:rhel_tus:8.6::appstream

cpe:/a:redhat:rhel_e4s:8.8::appstream

cpe:/a:redhat:rhel_tus:8.8::appstream

cpe:/a:redhat:rhel_e4s:9.0::appstream

cpe:/a:redhat:rhel_e4s:9.2::appstream

cpe:/a:redhat:rhel_eus:9.4::appstream

cpe:/a:redhat:rhel_eus:9.6::appstream

cpe:/a:redhat:enterprise_linux:9::appstream

cpe:/o:redhat:enterprise_linux_eus:10.0

cpe:/o:redhat:enterprise_linux:10.1

cpe:/o:redhat:enterprise_linux:8::baseos

cpe:/o:redhat:rhel_aus:8.2::baseos

cpe:/o:redhat:rhel_aus:8.4::baseos

cpe:/o:redhat:rhel_eus_long_life:8.4::baseos

cpe:/o:redhat:rhel_aus:8.6::baseos

cpe:/o:redhat:rhel_e4s:8.6::baseos

cpe:/o:redhat:rhel_tus:8.6::baseos

cpe:/o:redhat:rhel_e4s:8.8::baseos

cpe:/o:redhat:rhel_tus:8.8::baseos

cpe:/o:redhat:rhel_e4s:9.0::baseos

cpe:/o:redhat:rhel_e4s:9.2::baseos

cpe:/o:redhat:rhel_eus:9.4::baseos

cpe:/o:redhat:rhel_eus:9.6::baseos

cpe:/o:redhat:enterprise_linux:9::baseos

cpe:/a:redhat:enterprise_linux:8::highavailability

cpe:/a:redhat:rhel_aus:8.4::highavailability

cpe:/a:redhat:rhel_eus_long_life:8.4::highavailability

cpe:/a:redhat:rhel_e4s:8.6::highavailability

cpe:/a:redhat:rhel_tus:8.6::highavailability

cpe:/a:redhat:rhel_e4s:8.8::highavailability

cpe:/a:redhat:rhel_tus:8.8::highavailability

cpe:/a:redhat:rhel_e4s:9.0::highavailability

cpe:/a:redhat:rhel_e4s:9.2::highavailability

cpe:/a:redhat:rhel_eus:9.4::highavailability

cpe:/a:redhat:multicluster_globalhub:1.4::el9

cpe:/a:redhat:multicluster_globalhub:1.5::el9

cpe:/a:redhat:network_observ_optr:1.11::el9

cpe:/a:redhat:openshift_api_data_protection:1.3::el9

cpe:/a:redhat:ai_inference_server:3.2::el9

cpe:/a:redhat:acm:2.14::el9

cpe:/a:redhat:acm:2.15::el9

cpe:/a:redhat:advanced_cluster_security:4.8::el8

cpe:/a:redhat:advanced_cluster_security:4.9::el8

cpe:/a:redhat:ansible_automation_platform:2.4::el8

cpe:/a:redhat:ansible_automation_platform:2.5::el8

cpe:/a:redhat:ansible_automation_platform:2.6::el9

cpe:/a:redhat:ceph_storage:7.1::el9

cpe:/a:redhat:ceph_storage:8::el9

cpe:/a:redhat:ceph_storage:9::el10

cpe:/a:redhat:discovery:2::el9

cpe:/a:redhat:openshift_ai:2.25::el9

cpe:/a:redhat:openshift_ai:3.3::el9

cpe:/a:redhat:openshift_devspaces:3.26::el9

cpe:/a:redhat:openshift_gitops:1.17::el8

cpe:/a:redhat:openshift_gitops:1.18::el8

cpe:/a:redhat:openshift_gitops:1.19::el8

cpe:/a:redhat:quay:3.12::el8

cpe:/a:redhat:quay:3.13::el8

cpe:/a:redhat:quay:3.14::el8

cpe:/a:redhat:quay:3.15::el8

cpe:/a:redhat:quay:3.16::el9

cpe:/a:redhat:quay:3.10::el8

cpe:/a:redhat:trusted_artifact_signer:1.2::el9

cpe:/a:redhat:trusted_artifact_signer:1.3::el9

cpe:/a:redhat:rhui:5::el9

cpe:/a:redhat:enterprise_linux:8::resilientstorage

cpe:/a:redhat:rhel_e4s:9.0::resilientstorage

cpe:/a:redhat:rhel_e4s:9.2::resilientstorage

cpe:/a:redhat:rhel_eus:9.4::resilientstorage

cpe:/a:redhat:zero_trust_workload_identity_manager:1.0::el9

cpe:/a:redhat:cert_manager:1.18::el9

cpe:/a:redhat:mirror_registry:2.0::el8

cpe:/a:redhat:external_secrets_operator:1

cpe:/a:redhat:logging:5

cpe:/a:redhat:rhmt:1

cpe:/a:redhat:migration_toolkit_virtualization:2

cpe:/a:redhat:multiarch_tuning_operator

cpe:/a:redhat:multicluster_engine

cpe:/a:redhat:ocp_tools

cpe:/a:redhat:openshift_lightspeed

cpe:/a:redhat:openshift_pipelines:1

cpe:/a:redhat:serverless:1

cpe:/a:redhat:ai_inference_server:3

cpe:/a:redhat:ansible_automation_platform:2

cpe:/a:redhat:ansible_core:2

cpe:/a:redhat:quarkus:3

cpe:/a:redhat:certifications:9

cpe:/a:redhat:connectivity_link:1

cpe:/a:redhat:rhdh:1

cpe:/a:redhat:edge_manager:0

cpe:/o:redhat:enterprise_linux:10

cpe:/o:redhat:enterprise_linux:8

cpe:/o:redhat:enterprise_linux:9

cpe:/a:redhat:enterprise_linux_ai:3

cpe:/a:redhat:offline_knowledge_portal:1

cpe:/a:redhat:openshift_ai

cpe:/a:redhat:openshift:4

cpe:/a:redhat:openshift_data_foundation:4

cpe:/a:redhat:openshift_devspaces:3

cpe:/a:redhat:satellite:6

cpe:/a:redhat:zero_trust_workload_identity_manager:0

cpe:/a:redhat:assisted_installer:2

cpe:/a:redhat:confidential_compute_attestation:1

cpe:/a:redhat:dynamic_accelerator_slicer:1

cpe:/a:redhat:external_secrets_operator:0

cpe:/a:redhat:workload_availability_far:0

cpe:/a:redhat:workload_availability_nhc:0

cpe:/a:redhat:openshift_api_data_protection:1

cpe:/a:redhat:service_mesh:2

cpe:/a:redhat:service_mesh:3

cpe:/a:redhat:acm:2

cpe:/o:redhat:enterprise_linux:6

cpe:/o:redhat:enterprise_linux:7

cpe:/a:redhat:openshift_gitops:1

cpe:/a:redhat:openshift_update_service:5

cpe:/a:redhat:openstack:13

cpe:/a:redhat:openstack:16.2

cpe:/a:redhat:openstack:18.0

cpe:/a:redhat:quay:3

cpe:/a:redhat:workload_availability_snr:0

cpe:/a:redhat:stf:1.5

cpe:/a:redhat:enterprise_linux:8

cpe:/o:redhat:rhel_aus:8.2

cpe:/a:redhat:rhel_aus:8.4

cpe:/o:redhat:rhel_aus:8.4

cpe:/a:redhat:rhel_eus_long_life:8.4

cpe:/o:redhat:rhel_eus_long_life:8.4

cpe:/a:redhat:rhel_aus:8.6

cpe:/o:redhat:rhel_aus:8.6

cpe:/a:redhat:rhel_tus:8.6

cpe:/o:redhat:rhel_tus:8.6

cpe:/a:redhat:rhel_e4s:8.6

cpe:/o:redhat:rhel_e4s:8.6

cpe:/a:redhat:rhel_tus:8.8

cpe:/o:redhat:rhel_tus:8.8

cpe:/a:redhat:rhel_e4s:8.8

cpe:/o:redhat:rhel_e4s:8.8

cpe:/a:redhat:enterprise_linux:9

cpe:/a:redhat:rhel_e4s:9.0

cpe:/o:redhat:rhel_e4s:9.0

cpe:/a:redhat:rhel_e4s:9.2

cpe:/o:redhat:rhel_e4s:9.2

cpe:/a:redhat:rhel_eus:9.4

cpe:/o:redhat:rhel_eus:9.4

cpe:/a:redhat:rhel_eus:9.6

cpe:/o:redhat:rhel_eus:9.6

cpe:/a:redhat:logging:6

cpe:/a:redhat:rhmt:1.8::el8

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