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    CVE-2025-6433

    If a user visited a webpage with an invalid TLS certificate, and granted an exception, the webpage was able to provide a WebAuthn challenge that the user would be prompted to complete. This is in violation of the WebAuthN spec which requires "a secure transport established without errors". This vulnerability was fixed in Firefox 140 and Thunderbird 140.

    Published:Jun 24, 2025
    Last Modified:Apr 20, 2026
    EPS:Jun 24, 2025
    EPSS Score:0.0019
    CVSS Score:9.8

    Affected Products

    Vendor
    Mozilla
    Product
    Firefox

    Exploits

    No exploit reference

    Common Weakness Enumeration

    CWE-295 Improper Certificate Validation

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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