CVE-2021-22876

A vulnerability in curl during upload mishandles HTTP/2 RST_STREAM received from the server, leading to a use-after-free of a struct Curl_easy object.

When curl is asked to use a `.netrc` file for credentials and to follow HTTP redirects, it could leak the password used for the first host to the followed-to host under certain circumstances. This flaw only manifests if the netrc file has an entry matching the redirect target hostname.

When curl is told to use the Certificate Status Request TLS extension (OCSP stapling) to verify the server certificate, it might fail to detect some OCSP problems and wrongly consider the response as fine if the returned status reports another error than expected.

When curl is asked to use HSTS, the expiry time for a subdomain might overwrite a parent domain's cache entry, making it end sooner or later than otherwise intended. This affects applications using HSTS and URLs with the insecure HTTP:// scheme.

When curl uses a .netrc file for credentials and a URL with a username (without password) is specified, curl may wrongly retrieve and use the password of another user from .netrc for that host if no match exists for the specified user.

A double-free vulnerability has been found in the curl library's SASL authentication handling. The GSASL context is cleaned up twice without clearing the pointer, causing free() to be called on the same memory region twice.

A flaw in curl's cookie parsing logic allows a malicious HTTP server to set "super cookies" that bypass the Public Suffix List check, enabling injection of cookies that curl scopes and sends to unrelated third-party domains.

CVE-2023-38545 is a vulnerability related to heap buffer overflow during the SOCKS5 proxy handshake in curl. The issue arises when curl passes a hostname that is too long to the proxy, leading to incorrect data copying.

curl supports the `-t` command line option, known as `CURLOPT_TELNETOPTIONS` in libcurl. This rarely used option is used to send variable=content pairs to TELNET servers. Due to flaw in the option parser for sending `NEW_ENV` variables, libcurl could be made to pass on uninitialized data from a stack based buffer to the server. Therefore potentially revealing sensitive internal information to the server using a clear-text network protocol. This could happen because curl did not call and use sscanf() correctly when parsing the string provided by the application.

When curl is instructed to download content using the metalink feature, the contents 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 content from a set of different URLs, potentially hosted by different servers and the client can then download the file from one or several of them. In a serial or parallel manner. If one of the servers hosting the contents has been breached and the contents of the specific file on that server is replaced with a modified payload, curl should detect this when the hash of the file mismatches after a completed download. It should remove the contents and instead try getting the contents from another URL. This is not done, and instead such a hash mismatch is only mentioned in text and the potentially malicious content is kept in the file on disk.