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    CVE-2026-39831

    The Verify() method for FIDO/U2F security key types ([email protected], [email protected]) did not check the User Presence flag. Signatures generated without physical touch were accepted, allowing unattended use of a hardware security key. To restore the previous behavior, return a "no-touch-required" extension in Permissions.Extensions from PublicKeyCallback.

    Published:May 22, 2026
    Last Modified:Jun 2, 2026
    EPS:May 22, 2026
    EPSS Score:0.00029
    CVSS Score:9.1

    Affected Products

    Vendor
    Golang
    Product
    Crypto
    Vendor
    Golang
    Product
    Ssh

    Exploits

    No exploit reference

    Common Weakness Enumeration

    CWE-862 Missing Authorization

    Common Attack Pattern Enumeration and Classification (CAPEC)

    CAPEC-665 Exploitation of Thunderbolt Protection Flaws

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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