CWE-93
Improper Neutralization of CRLF Sequences ('CRLF Injection')
BaseDraft
Description
The product uses CRLF (carriage return line feeds) as a special element, e.g. to separate lines or records, but it does not neutralize or incorrectly neutralizes CRLF sequences from inputs.
Hierarchy (View 1000)
Related attack patterns (CAPEC)
CAPEC-15 · CAPEC-81
CVEs mapped to this weakness (73)
page 3 of 4| CVE | Sev | Risk | CVSS | EPSS | KEV | Published | Description |
|---|---|---|---|---|---|---|---|
| CVE-2016-6484 | Med | 0.40 | 6.1 | 0.00 | Jan 23, 2017 | CRLF injection vulnerability in Infoblox Network Automation NetMRI before 7.1.1 allows remote attackers to inject arbitrary HTTP headers and conduct HTTP response splitting attacks via the contentType parameter in a login action to config/userAdmin/login.tdf. | |
| CVE-2016-5331 | Med | 0.40 | 6.1 | 0.00 | Aug 8, 2016 | CRLF injection vulnerability in VMware vCenter Server 6.0 before U2 and ESXi 6.0 allows remote attackers to inject arbitrary HTTP headers and conduct HTTP response splitting attacks via unspecified vectors. | |
| CVE-2026-1299 | Med | 0.39 | — | 0.00 | Jan 23, 2026 | The email module, specifically the "BytesGenerator" class, didn’t properly quote newlines for email headers when serializing an email message allowing for header injection when an email is serialized. This is only applicable if using "LiteralHeader" writing headers that don't respect email folding rules, the new behavior will reject the incorrectly folded headers in "BytesGenerator". | |
| CVE-2026-0672 | Med | 0.39 | — | 0.00 | Jan 20, 2026 | When using http.cookies.Morsel, user-controlled cookie values and parameters can allow injecting HTTP headers into messages. Patch rejects all control characters within cookie names, values, and parameters. | |
| CVE-2025-57804 | Med | 0.38 | — | 0.00 | Aug 25, 2025 | h2 is a pure-Python implementation of a HTTP/2 protocol stack. Prior to version 4.3.0, an HTTP/2 request splitting vulnerability allows attackers to perform request smuggling attacks by injecting CRLF characters into headers. This occurs when servers downgrade HTTP/2 requests to HTTP/1.1 without properly validating header names/values, enabling attackers to manipulate request boundaries and bypass security controls. This issue has been patched in version 4.3.0. | |
| CVE-2026-1502 | Med | 0.37 | — | 0.00 | Apr 10, 2026 | CR/LF bytes were not rejected by HTTP client proxy tunnel headers or host. | |
| CVE-2026-35504 | Med | 0.36 | 5.5 | 0.00 | May 12, 2026 | PowerSYSTEM Center email notification service is affected by a CRLF injection vulnerability when using SMTPS communication. | |
| CVE-2026-2717 | Med | 0.36 | 5.5 | 0.00 | Apr 22, 2026 | The HTTP Headers plugin for WordPress is vulnerable to CRLF Injection in all versions up to, and including, 1.19.2. This is due to insufficient sanitization of custom header name and value fields before writing them to the Apache .htaccess file via `insert_with_markers()`. This makes it possible for authenticated attackers, with Administrator-level access and above, to inject arbitrary newline characters and additional Apache directives into the .htaccess configuration file via the 'Custom Headers' settings, leading to Apache configuration parse errors and potential site-wide denial of service. | |
| CVE-2024-51981 | Med | 0.35 | 5.3 | 0.01 | Jun 25, 2025 | An unauthenticated attacker may perform a blind server side request forgery (SSRF), due to a CLRF injection issue that can be leveraged to perform HTTP request smuggling. This SSRF leverages the WS-Addressing feature used during a WS-Eventing subscription SOAP operation. The attacker can control all the HTTP data sent in the SSRF connection, but the attacker can not receive any data back from this connection. | |
| CVE-2016-9964 | Med | 0.35 | 6.5 | 0.01 | Dec 16, 2016 | redirect() in bottle.py in bottle 0.12.10 doesn't filter a "\r\n" sequence, which leads to a CRLF attack, as demonstrated by a redirect("233\r\nSet-Cookie: name=salt") call. | |
| CVE-2026-41417 | Med | 0.34 | 5.3 | 0.00 | May 6, 2026 | 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. | |
| CVE-2026-42037 | Med | 0.34 | 5.3 | 0.00 | Apr 24, 2026 | 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. | |
| CVE-2026-2442 | Med | 0.34 | 5.3 | 0.00 | Mar 28, 2026 | 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. | |
| CVE-2026-3848 | Med | 0.33 | 5.0 | 0.00 | Mar 11, 2026 | GitLab has remediated an issue in GitLab CE/EE affecting all versions from 8.11 before 18.7.6, 18.8 before 18.8.6, and 18.9 before 18.9.2 that could have allowed an authenticated user to make unintended internal requests through proxy environments under certain conditions due to improper input validation in import functionality. | |
| CVE-2015-9097 | Med | 0.33 | 6.1 | 0.01 | Jun 12, 2017 | The mail gem before 2.5.5 for Ruby (aka A Really Ruby Mail Library) is vulnerable to SMTP command injection via CRLF sequences in a RCPT TO or MAIL FROM command, as demonstrated by CRLF sequences immediately before and after a DATA substring. | |
| CVE-2016-4993 | Med | 0.33 | 6.1 | 0.01 | Sep 26, 2016 | CRLF injection vulnerability in the Undertow web server in WildFly 10.0.0, as used in Red Hat JBoss Enterprise Application Platform (EAP) 7.x before 7.0.2, allows remote attackers to inject arbitrary HTTP headers and conduct HTTP response splitting attacks via unspecified vectors. | |
| CVE-2025-15282 | Med | 0.32 | — | 0.00 | Jan 20, 2026 | User-controlled data URLs parsed by urllib.request.DataHandler allow injecting headers through newlines in the data URL mediatype. | |
| CVE-2026-42258 | Med | 0.31 | — | 0.00 | May 9, 2026 | Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. Prior to versions 0.4.24, 0.5.14, and 0.6.4, symbol arguments to commands are vulnerable to a CRLF Injection / IMAP Command injection via Symbol arguments passed to IMAP commands. This issue has been patched in versions 0.4.24, 0.5.14, and 0.6.4. | |
| CVE-2026-42257 | Med | 0.31 | — | 0.00 | May 9, 2026 | Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. Prior to versions 0.4.24, 0.5.14, and 0.6.4, several Net::IMAP commands accept a raw string argument that is sent to the server without validation or escaping. If this string is derived from user-controlled input, it may contain contain CRLF sequences, which an attacker can use to inject arbitrary IMAP commands. This issue has been patched in versions 0.4.24, 0.5.14, and 0.6.4. | |
| CVE-2026-26962 | Med | 0.31 | 4.8 | 0.00 | Apr 2, 2026 | Rack is a modular Ruby web server interface. From version 3.2.0 to before version 3.2.6, Rack::Multipart::Parser unfolds folded multipart part headers incorrectly. When a multipart header contains an obs-fold sequence, Rack preserves the embedded CRLF in parsed parameter values such as filename or name instead of removing the folded line break during unfolding. As a result, applications that later reuse those parsed values in HTTP response headers may be vulnerable to downstream header injection or response splitting. This issue has been patched in version 3.2.6. |