cpp-httplib version v0.17.3 through v0.18.3 fails to filter CRLF characters ("\r\n") when those are prefixed with a null byte. This enables attackers to exploit CRLF injection that could further lead to HTTP Response Splitting, XSS, and more.

Gakido is a Python HTTP client focused on browser impersonation and anti-bot evasion. A vulnerability was discovered in Gakido prior to version 0.1.1 that allowed HTTP header injection through CRLF (Carriage Return Line Feed) sequences in user-supplied header values and names. When making HTTP requests with user-controlled header values containing `\r\n` (CRLF), `\n` (LF), or `\x00` (null byte) characters, an attacker could inject arbitrary HTTP headers into the request. The fix in version 0.1.1 adds a `_sanitize_header()` function that strips `\r`, `\n`, and `\x00` characters from both header names and values before they are included in HTTP requests.

All versions of the package ithewei/libhv are vulnerable to HTTP Response Splitting when untrusted user input is used to build headers values. An attacker can add the \r\n (carriage return line feeds) characters to end the HTTP response headers and inject malicious content, like for example additional headers or new response body, leading to a potential XSS vulnerability.

Prior to Apache HTTP Server 2.4.55, a malicious backend can cause the response headers to be truncated early, resulting in some headers being incorporated into the response body. If the later headers have any security purpose, they will not be interpreted by the client.

A vulnerability in Cisco Email Security Appliance (ESA) and Cisco Secure Email and Web Manager could allow an unauthenticated, remote attacker to conduct an HTTP response splitting attack. This vulnerability is due to the failure of the application or its environment to properly sanitize input values. An attacker could exploit this vulnerability by injecting malicious HTTP headers, controlling the response body, or splitting the response into multiple responses.