Review reviewHigh

CVE-2026-21441

urllib3 urllib3, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 10.0 Extended Update Support

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 en...

CVSS: 8.9
EPSS: 2.67%
CISA KEV: Not listed
Published: 2026.01.08

PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV

Exploit probability2.67%

Technical severityCVSS 8.9

Vulnerability overview

Affected product and versions

Product: urllib3 urllib3, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 10.0 Extended Update Support
Affected versions: >= >= 1.22, < 2.6.3, >= 1.22 < 2.6.3
Fixed versions: 2.6.3

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide

1
Identify
Confirm that urllib3 urllib3, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 10.0 Extended Update Support and an affected version are present.
2
Prioritize
Combine exploitation signals with asset exposure and business criticality.
3
Remediate
Follow the vendor advisory or supported update path and preserve rollback options.
4
Verify
Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector: 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/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
CWE: CWE-409