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CVE-2025-66418 Detail

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.


Metrics

NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

Nist CVSS score does not match with CNA score
CNA:  GitHub, Inc.
CVSS-B 8.9 HIGH
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

References to Advisories, Solutions, and Tools

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URL Source(s) Tag(s)
https://github.com/urllib3/urllib3/commit/24d7b67eac89f94e11003424bcf0d8f7b72222a8 GitHub, Inc.
https://github.com/urllib3/urllib3/security/advisories/GHSA-gm62-xv2j-4w53 GitHub, Inc.

Weakness Enumeration

CWE-ID CWE Name Source
CWE-770 Allocation of Resources Without Limits or Throttling GitHub, Inc.  

Change History

1 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2025-66418
NVD Published Date:
12/05/2025
NVD Last Modified:
12/05/2025
Source:
GitHub, Inc.