CURL-CVE-2021-22926

    Dashboard / Vulnerabilities / CURL-CVE-2021-22926

    CURL-CVE-2021-22926

    Published: 21 Jul 2021Last Modified: 27 May 2026

    Summary: CURLOPT_SSLCERT mix-up with Secure Transport

    Details: libcurl-using applications can ask for a specific client certificate to be used in a transfer. This is done with the `CURLOPT_SSLCERT` option (`--cert` with the command line tool). When libcurl is built to use the macOS native TLS library Secure Transport, an application can ask for the client certificate by name or with a filename - using the same option. If the name exists as a file, it is used instead of by name. If the application runs with a current working directory that is writable by other users (like `/tmp`), a malicious user can create a filename with the same name as the app wants to use by name, and thereby trick the application to use the file based cert instead of the one referred to by name making libcurl send the wrong client certificate in the TLS connection handshake.

    References:

    Affected packages

    Package

    Name:

    Purl:

    Affected ranges

    Type: SEMVER

    Events:

    Introduced- 7.33.0
    Fixed -7.78.0

    Affected versions

    7.77.0

    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
    CURL-CVE-2021-22926 | CVE-DB