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    CVE-2026-87866

    When built with wolfSSL, curl can successfully validate a pinned public key hash against a key the TLS peer does not possess. During the TLS handshake, wolfSSL validates the connection, but curl's subsequent re-parsing of the same certificate - tricked by a manipulated validity length field - extracts and matches a different embedded key, incorrectly authorizing the pinned public key.

    Published:Oct 14, 2026
    Last Modified:Oct 20, 2026
    EPS:Oct 20, 2026
    EPSS Score:
    CVSS Score:3.7

    Affected Products

    Vendor
    Curl
    Product
    Curl

    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