Daniel Stenberg reported the following vulnerability in cURL:

   libcurl can in some circumstances re-use the wrong connection when asked to
   do transfers using other protocols than HTTP and FTP.

   libcurl features a pool of recent connections so that subsequent requests
   can re-use an existing connection to avoid overhead.

   When re-using a connection a range of criterion must first be met. Due to an
   error in the code, a transfer that was initiated by an application could
   wrongfully re-use an existing connection to the same server that was
   authenticated using different credentials. The existing logic basically only
   worked well enough for HTTP and FTP, while all other network protocols were
   silently, but erroneously, assumed to work like HTTP. Basically, protocols
   that use connection oriented authentication need a new connection when new
   credentials are used.

   Affected protocols include: SCP, SFTP, POP3(S), IMAP(S), SMTP(S) and
   LDAP(S).

   Applications can disable libcurl's re-use of connections and thus mitigate
   this problem, by using one of the following libcurl options to alter how
   connections are or aren't re-used: CURLOPT_FRESH_CONNECT,
   CURLOPT_MAXCONNECTS and CURLMOPT_MAX_HOST_CONNECTIONS (if using curl_multi
   API).

   (This problem is very similar to a problem previously reported to NTLM HTTP
   connections, named CVE-2014-0015)

Versions 7.10.6 to and including 7.35.0 are affected. The flaw is fixed in version 7.36.0

Acknowledgements:

Red Hat would like to thank the cURL project for reporting this issue. Upstream acknowledges Steve Holme as the original reporter.