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Vulnerabilities

Vulnerability · CVE-2026-21441

urllib3 is an HTTP client library for Python.

Published Jan 7, 2026 · catalog updated Sep 17, 2026 · urllib3 is an HTTP

Last checked Oct 28, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2026-21441. EPSS is 2.92%. Act only if a listed version of urllib3 is an HTTP is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (urllib3 is an HTTP).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
High8.9
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
2.92%
Remediation
Version ranges on file
Affected products
vendor urllib3 urllib3 1.22, < 2.6.3

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 header (e.g., , , , or ). 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

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • vendor urllib3 urllib3 1.22, < 2.6.31.22, < 2.6.3

How to fix CVE-2026-21441

  • Upgrade

    CVE-2026-21441 lists a fix boundary at 2.6.3. Compare the installed build with that boundary before you change production.

  • Version check

    Affected < 2.6.3

  • Official advisories

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-21441. EPSS is 2.92%. Act only if a listed version of urllib3 is an HTTP is installed.

Which versions are affected?

Compare what you have installed with urllib3 urllib3 1.22, < 2.6.3 1.22, < 2.6.3. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 2.92%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Jan 7, 2026 · EUVD

    Detected

    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 header (e.g., , , , or ). When using the streaming API, the library decompresses only the necessary byt

  2. Sep 17, 2026 · EUVD

    Updated

    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 header (e.g., , , , or ). When using the streaming API, the library decompresses only the necessary byt

Sources

  • EUVDVulnerability recordEUVD-2026-1188

    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 b

    euvd.enisa.europa.eu

References

Freshness

Last verified in this catalog Sep 17, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • EUVDOct 28, 2026