| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| 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. |
| libcurl keeps previously used connections in a connection pool for subsequent
transfers to reuse if one of them matches the setup.
An easy handle that first uses default native CA trust can continue trusting
the native platform store after the application switches that same handle to
custom CA material for a later transfer. |
| The curl logic that works with SASL authentication could end up cleaning up
the GSASL context *twice* without clearing the pointer in between, making it
`free()` the same pointer twice. |
| An issue in curl’s QUIC UDP receive function allows a malicious HTTP/3 server
to trigger a remote denial of service against a curl or libcurl client.
Because the helper function discards zero-length UDP datagrams before counting
them toward the per-call packet budget, a connected QUIC peer can continuously
stream empty datagrams to indefinitely stall the client. |
| By default, curl automatically responds to WebSocket PING frames. Because curl
lacks an upper bound on memory allocation for unacknowledged frames, a
malicious server can exhaust all available memory by flooding curl with rapid,
sequential PING messages. |
| When reusing a libcurl handle for sequential transfers driven by
environment-variable proxy configuration, libcurl fails to clear the proxy
authentication state between requests. Specifically, if the initial transfer
authenticates against `proxyA` using Digest auth, a subsequent transfer routed
through `proxyB` erroneously leaks the `Proxy-Authorization:` header intended
solely for `proxyA`. |
| Calling `curl_easy_pause()` within the event-based `CURLMOPT_SOCKETFUNCTION`
callback triggers a use-after-free vulnerability, where libcurl attempts to
store a flag using a dangling struct pointer immediately after that pointer's
memory has been freed. |
| A vulnerability exists where a new transfer that uses STARTTLS to upgrade the
connection might reuse an existing live connection even though the TLS
configuration mismatches so it should not. |
| libcurl had a flaw that when instructed to clear proxy authentication
credentials which made it not do so, leaving the old credentials around to get
used for subsequent transfers that should not know nor use them. |
| 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`. |
| 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. |
| A flaw was found in curl. A remote attacker could exploit this by initiating an unencrypted connection (via IMAP, SMTP, or POP3) and then making a subsequent request to the same host that requires Transport Layer Security (TLS). Due to incorrect connection reuse, the subsequent request would bypass the TLS requirement, leading to the transmission of sensitive information in cleartext. This vulnerability, categorized as Cleartext Transmission of Sensitive Information (CWE-319), results in information disclosure. |
| A flaw was found in curl. When curl is configured to use distinct proxies for different URL schemes, a redirect from a URL using an authenticated proxy to one using an unauthenticated proxy can inadvertently expose the initial proxy's credentials. This improper credential management (CWE-522) may allow an attacker to gain unauthorized access or information by intercepting these disclosed credentials. |
| The redirect implementation in curl and libcurl 5.11 through 7.19.3, when CURLOPT_FOLLOWLOCATION is enabled, accepts arbitrary Location values, which might allow remote HTTP servers to (1) trigger arbitrary requests to intranet servers, (2) read or overwrite arbitrary files via a redirect to a file: URL, or (3) execute arbitrary commands via a redirect to an scp: URL. |
| Stack-based buffer overflow in the ntlm_output function in http-ntlm.c for (1) wget 1.10, (2) curl 7.13.2, and (3) libcurl 7.13.2, and other products that use libcurl, when NTLM authentication is enabled, allows remote servers to execute arbitrary code via a long NTLM username. |
| When an OAuth2 bearer token is used for an HTTP(S) transfer, and that transfer
performs a cross-protocol redirect to a second URL that uses an IMAP, LDAP,
POP3 or SMTP scheme, curl might wrongly pass on the bearer token to the new
target host. |
| 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 designed to work.
An application that allows Negotiate authentication to a server (that responds
wanting Negotiate) with `user1:password1` and then does another operation to
the same server also using Negotiate but with `user2:password2` (while the
previous connection is still alive) - the second request wrongly reused the
same connection and since it then sees that the Negotiate negotiation is
already made, it just sends the request over that connection thinking it uses
the user2 credentials when it is in fact still using the connection
authenticated for user1...
The set of authentication methods to use is set with `CURLOPT_HTTPAUTH`.
Applications can disable libcurl's reuse of connections and thus mitigate this
problem, by using one of the following libcurl options to alter how
connections are or are not reused: `CURLOPT_FRESH_CONNECT`,
`CURLOPT_MAXCONNECTS` and `CURLMOPT_MAX_HOST_CONNECTIONS` (if using the
curl_multi API). |
| 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. |
| 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 doing a second SMB request to the same host again, curl would wrongly use
a data pointer pointing into already freed memory. |
