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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:Sep 15, 2026
    EPS:Jul 3, 2026
    EPSS Score:0.00688
    CVSS Score:9.8

    Affected Products

    Vendor
    Curl
    Product
    Curl
    Vendor
    Haxx
    Product
    Curl
    Vendor
    Redhat
    Product
    Hummingbird

    Exploits

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

    Common Attack Pattern Enumeration and Classification (CAPEC)

    CAPEC-102 Session Sidejacking
    CAPEC-12 Choosing Message Identifier
    CAPEC-217 Exploiting Incorrectly Configured SSL/TLS
    CAPEC-509 Kerberoasting
    CAPEC-555 Remote Services with Stolen Credentials
    CAPEC-561 Windows Admin Shares with Stolen Credentials
    CAPEC-60 Reusing Session IDs (aka Session Replay)
    CAPEC-612 WiFi MAC Address Tracking
    CAPEC-613 WiFi SSID Tracking
    CAPEC-618 Cellular Broadcast Message Request
    CAPEC-619 Signal Strength Tracking
    CAPEC-621 Analysis of Packet Timing and Sizes
    CAPEC-622 Electromagnetic Side-Channel Attack
    CAPEC-623 Compromising Emanations Attack
    CAPEC-644 Use of Captured Hashes (Pass The Hash)
    CAPEC-645 Use of Captured Tickets (Pass The Ticket)
    CAPEC-652 Use of Known Kerberos Credentials
    CAPEC-701 Browser in the Middle (BiTM)
    CAPEC-94 Adversary in the Middle (AiTM)

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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