When doing a TFTP transfer and curl/libcurl is given a URL that contains a very long file name (longer than about 515 bytes), the file name is truncated to fit within the buffer boundaries, but the buffer size is still wrongly updated to use the untruncated length. This too large value is then used in the sendto() call, making curl attempt to send more data than what is actually put into the buffer. The endto() function will then read beyond the end of the heap based buffer. A malicious HTTP(S) server could redirect a vulnerable libcurl-using client to a crafted TFTP URL (if the client hasn't restricted which protocols it allows redirects to) and trick it to send private memory contents to a remote server over UDP. Limit curl's redirect protocols with --proto-redir and libcurl's with CURLOPT_REDIR_PROTOCOLS.
Multiple integer overflows in the (1) curl_escape, (2) curl_easy_escape, (3) curl_unescape, and (4) curl_easy_unescape functions in libcurl before 7.50.3 allow attackers to have unspecified impact via a string of length 0xffffffff, which triggers a heap-based buffer overflow.
curl and libcurl before 7.50.2, when built with NSS and the libnsspem.so library is available at runtime, allow remote attackers to hijack the authentication of a TLS connection by leveraging reuse of a previously loaded client certificate from file for a connection for which no certificate has been set, a different vulnerability than CVE-2016-5420.
Use-after-free vulnerability in libcurl before 7.50.1 allows attackers to control which connection is used or possibly have unspecified other impact via unknown vectors.
curl and libcurl before 7.50.1 do not check the client certificate when choosing the TLS connection to reuse, which might allow remote attackers to hijack the authentication of the connection by leveraging a previously created connection with a different client certificate.
curl and libcurl before 7.50.1 do not prevent TLS session resumption when the client certificate has changed, which allows remote attackers to bypass intended restrictions by resuming a session.
The default configuration for cURL and libcurl before 7.42.1 sends custom HTTP headers to both the proxy and destination server, which might allow remote proxy servers to obtain sensitive information by reading the header contents.
cURL and libcurl 7.10.6 through 7.41.0 do not properly re-use authenticated Negotiate connections, which allows remote attackers to connect as other users via a request.
The sanitize_cookie_path function in cURL and libcurl 7.31.0 through 7.41.0 does not properly calculate an index, which allows remote attackers to cause a denial of service (out-of-bounds write and crash) or possibly have other unspecified impact via a cookie path containing only a double-quote character.
cURL and libcurl 7.10.6 through 7.41.0 does not properly re-use NTLM connections, which allows remote attackers to connect as other users via an unauthenticated request, a similar issue to CVE-2014-0015.