CVE-2025-66418 | THREATINT

Description

urllib3 is a user-friendly HTTP client library for Python. Starting in version 1.24 and prior to 2.6.0, the number of links in the decompression chain was unbounded allowing a malicious server to insert a virtually unlimited number of compression steps leading to high CPU usage and massive memory allocation for the decompressed data. This vulnerability is fixed in 2.6.0.

PUBLISHED Reserved 2025-11-28 | Published 2025-12-05 | Updated 2025-12-05 | Assigner GitHub_M

HIGH: 8.9CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H

Problem types

CWE-770: Allocation of Resources Without Limits or Throttling

Product status

>= 1.24, < 2.6.0

affected

References

github.com/...rllib3/security/advisories/GHSA-gm62-xv2j-4w53

github.com/...ommit/24d7b67eac89f94e11003424bcf0d8f7b72222a8

cve.org (CVE-2025-66418)

nvd.nist.gov (CVE-2025-66418)