Net::Statsd::Lite versions through 0.10.0 for Perl allowed metric injections. The values from the set_add method were not checked for newlines, colons or pipes. Metrics generated from untrusted sources could inject additional statsd metrics. Note that version 0.9.0 fixed a similar issue CVE-2026-46719 for metric names.

Net::Statsd::Lite versions before 0.9.0 for Perl allowed metric injections. The metric names were not checked for newlines, colons or pipes. Metrics generated from untrusted sources could inject additional statsd metrics.

Net::Statsd::Tiny versions before 0.3.8 for Perl allowed metric injections. The metric names and set values were not checked for newlines, colons or pipes. Metrics generated from untrusted sources could inject additional statsd metrics.

The Page Builder: Pagelayer – Drag and Drop website builder plugin for WordPress is vulnerable to Improper Neutralization of CRLF Sequences ('CRLF Injection') in all versions up to, and including, 2.0.7. This is due to the contact form handler performing placeholder substitution on attacker-controlled form fields and then passing the resulting values into email headers without removing CR/LF characters. This makes it possible for unauthenticated attackers to inject arbitrary email headers (for example Bcc / Cc) and abuse form email delivery via the 'email' parameter granted they can target a contact form configured to use placeholders in mail template headers.

All versions of the package ithewei/libhv are vulnerable to CRLF Injection when untrusted user input is used to set request headers. An attacker can add the \r\n (carriage return line feeds) characters and inject additional headers in the request sent.

Improper Neutralization of CRLF Sequences ('CRLF Injection') vulnerability in benoitc hackney allows HTTP Response Splitting. The hackney_cookie:setcookie/3 function in src/hackney_cookie.erl validates the Name and Value arguments against CRLF and control characters, but concatenates the domain and path options verbatim into the output iolist with no equivalent check. An attacker who controls either option — for example by supplying a Host header value forwarded as the cookie domain, or a request path forwarded as the cookie path — can inject a literal CRLF sequence and arbitrary additional Set-Cookie headers into the HTTP response. This issue affects hackney: from 0.9.0 before 4.0.1.

eventsource-encoder encodes events as well-formed EventSource/Server Sent Event (SSE) messages. Prior to 1.0.2, eventsource-encoder does not sanitize the event or id fields of an EventSourceMessage before serializing them. An attacker who controls either field can inject arbitrary Server-Sent Events line terminators (\n, \r, or \r\n) and thereby forge additional SSE fields or entire messages on the stream. This vulnerability is fixed in 1.0.2.

Axios is a promise based HTTP client for the browser and Node.js. From 1.0.0 to before 1.15.1, the FormDataPart constructor in lib/helpers/formDataToStream.js interpolates value.type directly into the Content-Type header of each multipart part without sanitizing CRLF (\r\n) sequences. An attacker who controls the .type property of a Blob/File-like object (e.g., via a user-uploaded file in a Node.js proxy service) can inject arbitrary MIME part headers into the multipart form-data body. This bypasses Node.js v18+ built-in header protections because the injection targets the multipart body structure, not HTTP request headers. This vulnerability is fixed in 1.15.1.

Netty allows request-line validation to be bypassed when a `DefaultHttpRequest` or `DefaultFullHttpRequest` is created first and its URI is later changed via `setUri()`. The constructors reject CRLF and whitespace characters that would break the start-line, but `setUri()` does not apply the same validation. `HttpRequestEncoder` and `RtspEncoder` then write the URI into the request line verbatim. If attacker-controlled input reaches `setUri()`, this enables CRLF injection and insertion of additional HTTP or RTSP requests, leading to HTTP request smuggling or desynchronization on the HTTP side and request injection on the RTSP side. This issue is fixed in versions 4.2.13.Final and 4.1.133.Final.

MimeKit is a C# library which may be used for the creation and parsing of messages using the Multipurpose Internet Mail Extension (MIME), as defined by numerous IETF specifications. Prior to version 4.15.1, a CRLF injection vulnerability in MimeKit allows an attacker to embed \r\n into the SMTP envelope address local-part (when the local-part is a quoted-string). This is non-compliant with RFC 5321 and can result in SMTP command injection (e.g., injecting additional RCPT TO / DATA / RSET commands) and/or mail header injection, depending on how the application uses MailKit/MimeKit to construct and send messages. The issue becomes exploitable when the attacker can influence a MailboxAddress (MAIL FROM / RCPT TO) value that is later serialized to an SMTP session. RFC 5321 explicitly defines the SMTP mailbox local-part grammar and does not permit CR (13) or LF (10) inside Quoted-string (qtextSMTP and quoted-pairSMTP ranges exclude control characters). SMTP commands are terminated by <CRLF>, making CRLF injection in command arguments particularly dangerous. This issue has been patched in version 4.15.1.

Mailpit is an email testing tool and API for developers. Prior to version 1.28.3, Mailpit's SMTP server is vulnerable to Header Injection due to an insufficient Regular Expression used to validate `RCPT TO` and `MAIL FROM` addresses. An attacker can inject arbitrary SMTP headers (or corrupt existing ones) by including carriage return characters (`\r`) in the email address. This header injection occurs because the regex intended to filter control characters fails to exclude `\r` and `\n` when used inside a character class. Version 1.28.3 fixes this issue.

A flaw was found in libsoup. An attacker who can control the input for the Content-Disposition header can inject CRLF (Carriage Return Line Feed) sequences into the header value. These sequences are then interpreted verbatim when the HTTP request or response is constructed, allowing arbitrary HTTP headers to be injected. This vulnerability can lead to HTTP header injection or HTTP response splitting without requiring authentication or user interaction.

A flaw was found in libsoup, an HTTP client library. This vulnerability, known as CRLF (Carriage Return Line Feed) Injection, occurs when an HTTP proxy is configured and the library improperly handles URL-decoded input used to create the Host header. A remote attacker can exploit this by providing a specially crafted URL containing CRLF sequences, allowing them to inject additional HTTP headers or complete HTTP request bodies. This can lead to unintended or unauthorized HTTP requests being forwarded by the proxy, potentially impacting downstream services.

A vulnerability was found in Keycloak-services. Special characters used during e-mail registration may perform SMTP Injection and unexpectedly send short unwanted e-mails. The email is limited to 64 characters (limited local part of the email), so the attack is limited to very shorts emails (subject and little data, the example is 60 chars). This flaw's only direct consequence is an unsolicited email being sent from the Keycloak server. However, this action could be a precursor for more sophisticated attacks.

Music Player Daemon (MPD) before version 0.24.11 contains a CRLF injection vulnerability in the xspf_char_data function within the XSPF playlist plugin that allows attackers to embed literal CR/LF bytes in URI fields by supplying a malicious XSPF playlist with XML numeric character references. Attackers can inject forged key-value lines through the location field into MPD protocol responses including playlistinfo, currentsong, and listplaylist outputs, as well as the state file writer, by exploiting Expat's decoding of numeric character references prior to the character data callback.

A security vulnerability has been detected in Ritlabs TinyWeb Server 1.94. This vulnerability affects unknown code of the component Request Handler. The manipulation with the input %0D%0A leads to crlf injection. It is possible to initiate the attack remotely. The exploit has been disclosed publicly and may be used. Upgrading to version 1.99 is able to resolve this issue. The identifier of the patch is d49c3da6a97e950975b18626878f3ee1f082358e. It is suggested to upgrade the affected component. The vendor was contacted early about this disclosure but did not respond in any way.

undici is an HTTP/1.1 client, written from scratch for Node.js.`=< undici@5.8.0` users are vulnerable to _CRLF Injection_ on headers when using unsanitized input as request headers, more specifically, inside the `content-type` header. Example: ``` import { request } from 'undici' const unsanitizedContentTypeInput = 'application/json\r\n\r\nGET /foo2 HTTP/1.1' await request('http://localhost:3000, { method: 'GET', headers: { 'content-type': unsanitizedContentTypeInput }, }) ``` The above snippet will perform two requests in a single `request` API call: 1) `http://localhost:3000/` 2) `http://localhost:3000/foo2` This issue was patched in Undici v5.8.1. Sanitize input when sending content-type headers using user input as a workaround.

Pluto is a superset of Lua 5.4 with a focus on general-purpose programming. Scripts passing user-controlled values to http.request header values are affected. An attacker could use this to send arbitrary requests, potentially leveraging authentication tokens provided in the same headers table.

undici is an HTTP/1.1 client, written from scratch for Node.js. It is possible to inject CRLF sequences into request headers in undici in versions less than 5.7.1. A fix was released in version 5.8.0. Sanitizing all HTTP headers from untrusted sources to eliminate `\r\n` is a workaround for this issue.

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.

A vulnerability in the web-based Cisco IOx application hosting environment management interface of Cisco IOS XE Software could allow an unauthenticated, remote attacker to perform a carriage return line feed (CRLF) injection attack against a user. This vulnerability is due to insufficient validation of user input. An attacker could exploit this vulnerability by sending crafted packets to an affected device. A successful exploit could allow the attacker to arbitrarily inject log entries, manipulate the structure of log files, or obscure legitimate log events.

CRLF Injection vulnerability in Limesurvey v2.65.1+170522.  This vulnerability could allow a remote attacker to inject arbitrary HTTP headers and perform HTTP response splitting attacks via '/index.php/survey/index/sid/<SID>/token/fwyfw%0d%0aCookie:%20POC'.

aiohttp is an asynchronous HTTP client/server framework for asyncio and Python. Improper validation makes it possible for an attacker to modify the HTTP request (e.g. insert a new header) or even create a new HTTP request if the attacker controls the HTTP method. The vulnerability occurs only if the attacker can control the HTTP method (GET, POST etc.) of the request. If the attacker can control the HTTP version of the request it will be able to modify the request (request smuggling). This issue has been patched in version 3.9.0.