| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| When curl is told to use the Certificate Status Request TLS extension, often
referred to as *OCSP stapling*, to verify that the server certificate is
valid, it fails to detect OCSP problems and instead wrongly consider the
response as fine. |
| 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. |
| 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. |
| 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`. |
| 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 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 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:password1` and then does another operation to the same server asking
for any authentication method but for `user2:password2` (while the previous
connection is still alive) - the second request gets confused and wrongly
reuses the same connection and sends the new request over that connection
thinking it uses a mix of user1's and user2's credentials when it is in fact
still using the connection authenticated for user1... |
| 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 happens, the same credentials
are used and the server name is the same. |
| When saving HSTS data to an excessively long file name, curl could end up
removing all contents, making subsequent requests using that file unaware of
the HSTS status they should otherwise use. |
| This flaw allows a malicious HTTP server to set "super cookies" in curl that
are then passed back to more origins than what is otherwise allowed or
possible. This allows a site to set cookies that then would get sent to
different and unrelated sites and domains.
It could do this by exploiting a mixed case flaw in curl's function that
verifies a given cookie domain against the Public Suffix List (PSL). For
example a cookie could be set with `domain=co.UK` when the URL used a lower
case hostname `curl.co.uk`, even though `co.uk` is listed as a PSL domain. |
| This flaw allows an attacker to insert cookies at will into a running program
using libcurl, if the specific series of conditions are met.
libcurl performs transfers. In its API, an application creates "easy handles"
that are the individual handles for single transfers.
libcurl provides a function call that duplicates en easy handle called
[curl_easy_duphandle](https://curl.se/libcurl/c/curl_easy_duphandle.html).
If a transfer has cookies enabled when the handle is duplicated, the
cookie-enable state is also cloned - but without cloning the actual
cookies. If the source handle did not read any cookies from a specific file on
disk, the cloned version of the handle would instead store the file name as
`none` (using the four ASCII letters, no quotes).
Subsequent use of the cloned handle that does not explicitly set a source to
load cookies from would then inadvertently load cookies from a file named
`none` - if such a file exists and is readable in the current directory of the
program using libcurl. And if using the correct file format of course. |
| This flaw makes curl overflow a heap based buffer in the SOCKS5 proxy
handshake.
When curl is asked to pass along the host name to the SOCKS5 proxy to allow
that to resolve the address instead of it getting done by curl itself, the
maximum length that host name can be is 255 bytes.
If the host name is detected to be longer, curl switches to local name
resolving and instead passes on the resolved address only. Due to this bug,
the local variable that means "let the host resolve the name" could get the
wrong value during a slow SOCKS5 handshake, and contrary to the intention,
copy the too long host name to the target buffer instead of copying just the
resolved address there.
The target buffer being a heap based buffer, and the host name coming from the
URL that curl has been told to operate with. |
| curl supports the `-t` command line option, known as `CURLOPT_TELNETOPTIONS`in libcurl. This rarely used option is used to send variable=content pairs toTELNET servers.Due to flaw in the option parser for sending `NEW_ENV` variables, libcurlcould be made to pass on uninitialized data from a stack based buffer to theserver. Therefore potentially revealing sensitive internal information to theserver using a clear-text network protocol.This could happen because curl did not call and use sscanf() correctly whenparsing the string provided by the application. |
| libcurl would reuse a previously created connection even when a TLS or SSHrelated option had been changed that should have prohibited reuse.libcurl keeps previously used connections in a connection pool for subsequenttransfers to reuse if one of them matches the setup. However, several TLS andSSH settings were left out from the configuration match checks, making themmatch too easily. |
| libcurl provides the `CURLOPT_CERTINFO` option to allow applications torequest details to be returned about a server's certificate chain.Due to an erroneous function, a malicious server could make libcurl built withNSS get stuck in a never-ending busy-loop when trying to retrieve thatinformation. |
| An improper authentication vulnerability exists in curl 7.33.0 to and including 7.82.0 which might allow reuse OAUTH2-authenticated connections without properly making sure that the connection was authenticated with the same credentials as set for this transfer. This affects SASL-enabled protocols: SMPTP(S), IMAP(S), POP3(S) and LDAP(S) (openldap only). |
| When curl >= 7.20.0 and <= 7.78.0 connects to an IMAP or POP3 server to retrieve data using STARTTLS to upgrade to TLS security, the server can respond and send back multiple responses at once that curl caches. curl would then upgrade to TLS but not flush the in-queue of cached responses but instead continue using and trustingthe responses it got *before* the TLS handshake as if they were authenticated.Using this flaw, it allows a Man-In-The-Middle attacker to first inject the fake responses, then pass-through the TLS traffic from the legitimate server and trick curl into sending data back to the user thinking the attacker's injected data comes from the TLS-protected server. |
| A user can tell curl >= 7.20.0 and <= 7.78.0 to require a successful upgrade to TLS when speaking to an IMAP, POP3 or FTP server (`--ssl-reqd` on the command line or`CURLOPT_USE_SSL` set to `CURLUSESSL_CONTROL` or `CURLUSESSL_ALL` withlibcurl). This requirement could be bypassed if the server would return a properly crafted but perfectly legitimate response.This flaw would then make curl silently continue its operations **withoutTLS** contrary to the instructions and expectations, exposing possibly sensitive data in clear text over the network. |
| When curl is instructed to download content using the metalink feature, thecontents is verified against a hash provided in the metalink XML file.The metalink XML file points out to the client how to get the same contentfrom a set of different URLs, potentially hosted by different servers and theclient can then download the file from one or several of them. In a serial orparallel manner.If one of the servers hosting the contents has been breached and the contentsof the specific file on that server is replaced with a modified payload, curlshould detect this when the hash of the file mismatches after a completeddownload. It should remove the contents and instead try getting the contentsfrom another URL. This is not done, and instead such a hash mismatch is onlymentioned in text and the potentially malicious content is kept in the file ondisk. |
| curl 7.21.0 to and including 7.73.0 is vulnerable to uncontrolled recursion due to a stack overflow issue in FTP wildcard match parsing. |
