CVE-2025-66418
Last modified
CVE-2025-66418 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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. EPSS estimates a 0.62% chance of exploitation in the next 30 days.
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
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
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
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Python | Urllib3 | >= 1.24, < 2.6.0 |
References
Timeline
- Published
- Last Modified
- Status
- Analyzed
Frequently Asked Questions
What is CVE-2025-66418?
How severe is CVE-2025-66418?
How do I fix CVE-2025-66418?
How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
- Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
- PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
- AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.
Related CVEs from 2025
- CVE-2025-66412Angular is a development platform for building mobile and de…5.4
- CVE-2025-66413Git for Windows is the Windows port of Git. Prior to 2.53.0(…6.5
- CVE-2025-66414MCP TypeScript SDK is the official TypeScript SDK for Model …8.1
- CVE-2025-66415fastify-reply-from is a Fastify plugin to forward the curren…5.4
- CVE-2025-66416The MCP Python SDK, called `mcp` on PyPI, is a Python implem…8.1
- CVE-2025-66417GLPI is a free asset and IT management software package. Fro…9.8
- CVE-2025-66419MaxKB is an open-source AI assistant for enterprise. In vers…10
- CVE-2025-6642PDF-XChange Editor U3D File Parsing Out-Of-Bounds Read Remot…7.8
- CVE-2025-66420Tryton sao (aka tryton-sao) before 7.6.9 allows XSS via an H…5.4
- CVE-2025-66421Tryton sao (aka tryton-sao) before 7.6.11 allows XSS because…5.4
- CVE-2025-66422Tryton trytond before 7.6.11 allows remote attackers to obta…4.3
- CVE-2025-66423Tryton trytond 6.0 before 7.6.11 does not enforce access rig…7.1
Are you affected by CVE-2025-66418?
Run a free Strix scan to check your systems for this vulnerability.
Scan your code nowSource: NVD / NIST