CURL-CVE-2021-22946

    Dashboard / Vulnerabilities / CURL-CVE-2021-22946

    CURL-CVE-2021-22946

    Published: 15 Sept 2021Last Modified: 27 May 2026

    Summary: Protocol downgrade required TLS bypassed

    Details: A user can tell curl to **require** a successful upgrade to TLS when speaking to an IMAP, POP3 or FTP server (`--ssl-reqd` on the command line or `CURLOPT_USE_SSL` set to `CURLUSESSL_CONTROL` or `CURLUSESSL_ALL` with libcurl). This requirement could be bypassed if the server would return a properly crafted but perfectly legitimate response. This flaw would then make curl silently continue its operations **without TLS** contrary to the instructions and expectations, exposing possibly sensitive data in clear text over the network.

    References:

    Affected packages

    Package

    Name:

    Purl:

    Affected ranges

    Type: SEMVER

    Events:

    Introduced- 7.20.0
    Fixed -7.79.0

    Affected versions

    7.78.0

    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-2021-22946 | CVE-DB