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    CVE-2026-11856

    Successfully using libcurl to do a transfer to a specific HTTP origin (`hostA`) with **Digest** authentication and then changing the origin to a different one (`hostB`) for a second transfer, reusing the same handle, makes libcurl wrongly pass on the `Authorization:` header field meant for `hostA`, to `hostB`.

    Published:Jul 3, 2026
    Last Modified:Jul 9, 2026
    EPS:Jul 3, 2026
    EPSS Score:0.00771
    CVSS Score:9.8

    Affected Products

    Vendor
    Curl
    Product
    Curl
    Vendor
    Redhat
    Product
    Hummingbird

    Exploits

    https://hackerone.com/reports/3793260https://hackerone.com/reports/3793260

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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