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    CVE-2025-66418

    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:Dec 5, 2025
    Last Modified:Dec 10, 2025
    EPS:Dec 5, 2025
    EPSS Score:0.00014
    CVSS Score:7.5

    Affected Products

    Vendor
    Python
    Product
    Urllib3
    Vendor
    Urllib3
    Product
    Urllib3

    Exploits

    No exploit reference

    Related CVEs

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    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High