SecuriTricks - CVE-2025-66418

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.

Product(s) Impacted

Vendor	Product	Versions
Python	Urllib3	*

Weaknesses

Common security weaknesses mapped to this vulnerability.

CWE-770

Allocation of Resources Without Limits or Throttling

The product allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor.

*CPE(s)

Affected systems and software identified for this CVE.

Type	Vendor	Product	Version	Update	Edition	Language	Software Edition	Target Software	Target Hardware	Other Information
a	python	urllib3	/	/	/	/	/	/	/	/

References

https://github.com/urllib3/urllib3/commit/24d7b67eac89f94e11003424bcf0d8f7b72222a8

https://github.com/urllib3/urllib3/security/advisories/GHSA-gm62-xv2j-4w53

CVSS Score

8.9 / 10

CVSS Data - 4.0

Attack Vector: NETWORK
Attack Complexity: LOW
Attack Requirements: PRESENT
Privileges Required: NONE
User Interaction: NONE
Scope:
Confidentiality Impact: NONE
Integrity Impact: NONE
Availability Impact: HIGH
Exploit Maturity: NOT_DEFINED

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

View Vector String

Timeline

Published: Dec. 5, 2025, 4:15 p.m.
Last Modified: Dec. 10, 2025, 4:08 p.m.

Status : Analyzed

CVE has had analysis completed and all data associations made.

More info

Source

security-advisories@github.com

CVE-2025-66418