Haxx libcurl 7.42.0

libcurl may read outside of a heap allocated buffer when doing FTP. When libcurl connects to an FTP server and successfully logs in (anonymous or not), it asks the server for the current directory with the `PWD` command. The server then responds with a 257 response containing the path, inside double quotes. The returned path name is then kept by libcurl for subsequent uses. Due to a flaw in the string parser for this directory name, a directory name passed like this but without a closing double quote would lead to libcurl not adding a trailing NUL byte to the buffer holding the name. When libcurl would then later access the string, it could read beyond the allocated heap buffer and crash or wrongly access data beyond the buffer, thinking it was part of the path. A malicious server could abuse this fact and effectively prevent libcurl-based clients to work with it - the PWD command is always issued on new FTP connections and the mistake has a high chance of causing a segfault. The simple fact that this has issue remained undiscovered for this long could suggest that malformed PWD responses are rare in benign servers. We are not aware of any exploit of this flaw. This bug was introduced in commit [415d2e7cb7](https://github.com/curl/curl/commit/415d2e7cb7), March 2005. In libcurl version 7.56.0, the parser always zero terminates the string but also rejects it if not terminated properly with a final double quote.

Published: 2017-10-06T13:00:00.000Z
Updated: 2024-08-05T22:00:39.675Z

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.

Published: 2017-10-04T01:00:00.000Z
Updated: 2026-04-16T13:34:51.252Z

The smb_request_state function in cURL and libcurl 7.40.0 through 7.42.1 allows remote SMB servers to obtain sensitive information from memory or cause a denial of service (out-of-bounds read and crash) via crafted length and offset values.

Published: 2015-06-22T19:00:00.000Z
Updated: 2024-08-06T05:39:32.139Z

cURL and libcurl 7.40.0 through 7.42.1 send the HTTP Basic authentication credentials for a previous connection when reusing a reset (curl_easy_reset) connection handle to send a request to the same host name, which allows remote attackers to obtain sensitive information via unspecified vectors.

Published: 2015-06-22T19:00:00.000Z
Updated: 2024-08-06T05:39:32.230Z