A use-after-free vulnerability exists in libcurl when an application
configures an HTTP/2 stream-dependency tree via `CURLOPT_STREAM_DEPENDS` or
`CURLOPT_STREAM_DEPENDS_E`, subsequently invokes `curl_easy_reset()`, and
finally terminates the handle with `curl_easy_cleanup()`. During this final
cleanup phase, libcurl attempts to access and modify an internal structure
that was already freed during the reset operation.
Successfully using libcurl to do a transfer over a specific HTTP proxy
(`proxyA`) with **Digest** authentication and then changing the proxy host to
a second one (`proxyB`) for a second transfer, reusing the same handle, makes
libcurl wrongly pass on the `Proxy-Authorization:` header field meant for
`proxyA`, to `proxyB`.
netrc credential leak with reused proxy connection
When asked to both use a `.netrc` file for credentials and to follow HTTP
redirects, libcurl could leak the password used for the first host to the
followed-to host under certain circumstances.
Using libcurl, when a custom `Host:` header is first set for an HTTP request
and a second request is subsequently done using the same *easy handle* but
without the custom `Host:` header set, the second request would use stale
information and pass on cookies meant for the first host in the second
request. Leak them.
curl might erroneously pass on credentials for a first proxy to a second
proxy.
This can happen when the following conditions are true:
1. curl is setup to use specific different proxies for different URL schemes
2. the first proxy needs credentials
3. the second proxy uses no credentials
4. while using the first proxy (using say `http://`), curl is asked to follow
a redirect to a URL using another scheme (say `https://`), accessed using a
second, different, proxy
libcurl might in some circumstances reuse the wrong connection for SMB(S)
transfers.
libcurl features a pool of recent connections so that subsequent requests can
reuse an existing connection to avoid overhead.
When reusing a connection a range of criteria must be met. Due to a logical
error in the code, a network transfer operation that was requested by an
application could wrongfully reuse an existing SMB connection to the same
server that was using a different "share" than the new subsequent transfer
should.
This could in unlucky situations lead to the download of the wrong file or the
upload of a file to the wrong place. When this happ
libcurl might in some circumstances reuse the wrong connection when asked to
do an authenticated HTTP(S) request after a Negotiate-authenticated one, when
both use the same host.
libcurl features a pool of recent connections so that subsequent requests can
reuse an existing connection to avoid overhead.
When reusing a connection a range of criteria must be met. Due to a logical
error in the code, a request that was issued by an application could
wrongfully reuse an existing connection to the same server that was
authenticated using different credentials.
An application that first uses Negotiate authentication to a server with
`user1:passwo
A vulnerability exists where a connection requiring TLS incorrectly reuses an
existing unencrypted connection from the same connection pool. If an initial
transfer is made in clear-text (via IMAP, SMTP, or POP3), a subsequent request
to that same host bypasses the TLS requirement and instead transmit data
unencrypted.
curl would wrongly reuse an existing HTTP proxy connection doing CONNECT to a
server, even if the new request uses different credentials for the HTTP proxy.
The proper behavior is to create or use a separate connection.
When an OAuth2 bearer token is used for an HTTP(S) transfer, and that transfer
performs a redirect to a second URL, curl could leak that token to the second
hostname under some circumstances.
If the hostname that the first request is redirected to has information in the
used .netrc file, with either of the `machine` or `default` keywords, curl
would pass on the bearer token set for the first host also to the second one.
libcurl can in some circumstances reuse the wrong connection when asked to do
an Negotiate-authenticated HTTP or HTTPS request.
libcurl features a pool of recent connections so that subsequent requests can
reuse an existing connection to avoid overhead.
When reusing a connection a range of criterion must first be met. Due to a
logical error in the code, a request that was issued by an application could
wrongfully reuse an existing connection to the same server that was
authenticated using different credentials. One underlying reason being that
Negotiate sometimes authenticates *connections* and not *requests*, contrary
to how HTTP is design