Published: 23 June 2011
The Curl_input_negotiate function in http_negotiate.c in libcurl 7.10.6 through 7.21.6, as used in curl and other products, always performs credential delegation during GSSAPI authentication, which allows remote servers to impersonate clients via GSSAPI requests.
From the Ubuntu security team
Richard Silverman discovered that when doing GSSAPI authentication, libcurl unconditionally performs credential delegation, handing the server a copy of the client's security credential. (CVE-2011-2192)