Vulnerabilities (CVE)

Filtered by vendor Haxx Subscribe
Total 209 CVE
CVE Vendors Products Updated CVSS v2 CVSS v3
CVE-2026-6276 1 Haxx 1 Curl 2026-09-15 N/A 7.5 HIGH
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.
CVE-2026-6253 1 Haxx 1 Curl 2026-09-15 N/A 5.9 MEDIUM
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
CVE-2026-5773 1 Haxx 1 Curl 2026-09-15 N/A 7.5 HIGH
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.
CVE-2026-5545 1 Haxx 1 Curl 2026-09-15 N/A 6.5 MEDIUM
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...
CVE-2026-4873 1 Haxx 1 Curl 2026-09-15 N/A 5.9 MEDIUM
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.
CVE-2026-3784 1 Haxx 1 Curl 2026-09-15 N/A 6.5 MEDIUM
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.
CVE-2026-3783 1 Haxx 1 Curl 2026-09-15 N/A 5.3 MEDIUM
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.
CVE-2026-1965 1 Haxx 1 Curl 2026-09-15 N/A 6.5 MEDIUM
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 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).
CVE-2026-19931 1 Haxx 1 Curl 2026-09-15 N/A 9.8 CRITICAL
A flaw in libcurl makes it wrongly reuse an HTTP connection setup for a given hostname using Negotiate authentication, when the initial request is done using empty credentials. This can make user B's request get sent over user A's previously authenticated connection.
CVE-2026-18924 1 Haxx 1 Curl 2026-09-15 N/A 9.1 CRITICAL
A flaw in libcurl's handling of HTTP/2 Server Push streams, when the parent handle is set to share connections with other handles, can lead to use-after-free in the cleanup process.
CVE-2026-13608 1 Haxx 1 Curl 2026-09-15 N/A 7.4 HIGH
A flaw in the libcurl SASL negotiation for LDAP authentication allows an incomplete handshake sequence to be misinterpreted as a successful cryptographic verification. An attacker executing a Man-in-the-Middle (MITM) attack can inject a premature or shortcut response that bypasses complete peer validation.
CVE-2026-12064 1 Haxx 1 Curl 2026-09-15 N/A 7.5 HIGH
When a user invokes curl using a schemeless URL combined with `--proto-default` sftp (or scp), a disconnect occurs between the tool layer and libcurl. The tool layer incorrectly infers the URL scheme, which erroneously bypasses the initialization of critical SSH security options like CURLOPT_SSH_HOST_PUBLIC_KEY_SHA256 and CURLOPT_SSH_KNOWNHOSTS. Conversely, the libcurl runtime successfully honors CURLOPT_DEFAULT_PROTOCOL and establishes the connection via SFTP/SCP as specified. Because the tool layer skipped the security configuration, these SSH host verification options are silently omitted, causing curl to connect to an unverified SSH remote host without throwing an error.
CVE-2026-11856 1 Haxx 1 Curl 2026-09-15 N/A 9.8 CRITICAL
Successfully using libcurl to do a transfer to a specific HTTP origin (`hostA`) with **Digest** authentication and then changing the origin to a different one (`hostB`) for a second transfer, reusing the same handle, makes libcurl wrongly pass on the `Authorization:` header field meant for `hostA`, to `hostB`.
CVE-2026-11586 1 Haxx 1 Curl 2026-09-15 N/A 7.5 HIGH
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.
CVE-2026-11564 1 Haxx 1 Curl 2026-09-15 N/A 9.1 CRITICAL
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.
CVE-2026-11352 1 Haxx 1 Curl 2026-09-15 N/A 7.5 HIGH
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.
CVE-2026-10536 1 Haxx 1 Curl 2026-09-15 N/A 9.8 CRITICAL
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.
CVE-2025-15224 1 Haxx 1 Curl 2026-09-15 N/A 3.1 LOW
When doing SSH-based transfers using either SCP or SFTP, and asked to do public key authentication, curl would wrongly still ask and authenticate using a locally running SSH agent.
CVE-2025-15079 1 Haxx 1 Curl 2026-09-15 N/A 5.3 MEDIUM
When doing SSH-based transfers using either SCP or SFTP, and setting the known_hosts file, libcurl could still mistakenly accept connecting to hosts *not present* in the specified file if they were added as recognized in the libssh *global* known_hosts file.
CVE-2025-14819 1 Haxx 1 Curl 2026-09-15 N/A 5.3 MEDIUM
When doing TLS related transfers with reused easy or multi handles and altering the `CURLSSLOPT_NO_PARTIALCHAIN` option, libcurl could accidentally reuse a CA store cached in memory for which the partial chain option was reversed. Contrary to the user's wishes and expectations. This could make libcurl find and accept a trust chain that it otherwise would not.