CVE-2021-22926

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 file name - using the same option. If the name exists as a file, it will be used instead of by name.If the appliction runs with a current working directory that is writable by other users (like /tmp), a malicious user can create a file name 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.

curl as shipped with dotnet-3.1 is not affected by this flaw because it is not built with --with-secure-transport and does not use the Secure Transport backend. It uses openssl.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.