Weakness (CWE)
CWE-113: Improper Neutralization of CRLF Sequences in HTTP Headers
The product receives data from an HTTP agent/component (e.g., web server, proxy, browser, etc.), but it does not neutralize or incorrectly neutralizes CR and LF characters before the data is included in outgoing HTTP headers.
More detail
HTTP agents or components may include a web server, load balancer, reverse proxy, web caching proxy, application firewall, web browser, etc. Regardless of the role, they are expected to maintain coherent, consistent HTTP communication state across all components. However, including unexpected data in an HTTP header allows an attacker to specify the entirety of the HTTP message that is rendered by the client HTTP agent (e.g., web browser) or back-end HTTP agent (e.g., web server), whether the message is part of a request or a response.
When an HTTP request contains unexpected CR and LF characters, the server may respond with an output stream that is interpreted as "splitting" the stream into two different HTTP messages instead of one. CR is carriage return, also given by %0d or \r, and LF is line feed, also given by %0a or \n.
In addition to CR and LF characters, other valid/RFC compliant special characters and unique character encodings can be utilized, such as HT (horizontal tab, also given by %09 or \t) and SP (space, also given as + sign or %20).
These types of unvalidated and unexpected data in HTTP message headers allow an attacker to control the second "split" message to mount attacks such as server-side request forgery, cross-site scripting, and cache poisoning attacks.
How to prevent it (4 mitigations)
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Implementation
Construct HTTP headers very carefully, avoiding the use of non-validated input data.
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Implementation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. If an input does not strictly conform to specifications, reject it or transform it into something that conforms.
When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue."
Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
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Implementation
Use and specify an output encoding that can be handled by the downstream component that is reading the output. Common encodings include ISO-8859-1, UTF-7, and UTF-8. When an encoding is not specified, a downstream component may choose a different encoding, either by assuming a default encoding or automatically inferring which encoding is being used, which can be erroneous. When the encodings are inconsistent, the downstream component might treat some character or byte sequences as special, even if they are not special in the original encoding. Attackers might then be able to exploit this discrepancy and conduct injection attacks; they even might be able to bypass protection mechanisms that assume the original encoding is also being used by the downstream component.
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Implementation
Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174). Such errors could be used to bypass allowlist validation schemes by introducing dangerous inputs after they have been checked.
Source: MITRE CWE-113
127 results · Feed
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Low 2.4
HTTP Server incorrectly accepting disallowed characters within header values
Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting') vulnerability in Payara Platform Payara Server (Grizzly, REST Management Interface modules), Payara Platform Payara Micro (Grizzly modules) allows Manipulating State…
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Medium 6.4
An Improper Neutralization of CRLF Sequences in HTTP Headers ('http response splitting') vulnerability [CWE-113] in For…
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Medium 6.1
CRLF Injection in RestSharp's `RestRequest.AddHeader` method
RestSharp is a Simple REST and HTTP API Client for .NET. The second argument to `RestRequest.AddHeader` (the header value) is vulnerable to CRLF injection. The same applies to `RestRequest.AddOrUpdateHeader` and `RestClient.AddDefaultHeader`. The way HTTP hea…
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Medium 4.0
Cilium's Gateway API route matching order contradicts specification
Cilium is a networking, observability, and security solution with an eBPF-based dataplane. In the 1.15 branch prior to 1.15.8 and the 1.16 branch prior to 1.16.1, Gateway API HTTPRoutes and GRPCRoutes do not follow the match precedence specified in the Gatewa…
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Critical 9.8CVE-2024-40324 Public exploit
A CRLF injection vulnerability in E-Staff v5.1 allows attackers to insert Carriage Return (CR) and Line Feed (LF) chara…
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Medium 6.1
A vulnerability in the web-based management API of Cisco AsyncOS Software for Cisco Secure Email Gateway could allow an…
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Medium 6.3
Apache HTTP Server: HTTP Response Splitting in multiple modules
HTTP Response splitting in multiple modules in Apache HTTP Server allows an attacker that can inject malicious response headers into backend applications to cause an HTTP desynchronization attack. Users are recommended to upgrade to version 2.4.59, which fixe…
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Medium 6.8
trillium-http and trillium-client vulnerable to HTTP Request/Response Splitting
Trillium is a composable toolkit for building internet applications with async rust. In `trillium-http` prior to 0.3.12 and `trillium-client` prior to 0.5.4, insufficient validation of outbound header values may lead to request splitting or response splitting…
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Medium 5.3
The vulnerability allows a remote attacker to inject arbitrary HTTP response headers or manipulate HTTP response bodies…
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Medium 5.3
All versions of the package ithewei/libhv are vulnerable to HTTP Response Splitting when untrusted user input is used t…
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Medium 5.4
Mastodon Server-Side Request Forgery vulnerability
Mastodon is a free, open-source social network server based on ActivityPub. Starting in version 4.2.0-beta1 and prior to version 4.2.0-rc2, by crafting specific input, attackers can inject arbitrary data into HTTP requests issued by Mastodon. This can be used…
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Unscored —
Apache Flink Stateful Functions allowed HTTP header injection due to Improper Neutralization of CRLF Sequences
Improper Neutralization of CRLF Sequences in HTTP Headers in Apache Flink Stateful Functions 3.1.0, 3.1.1 and 3.2.0 allows remote attackers to inject arbitrary HTTP headers and conduct HTTP response splitting attacks via crafted HTTP requests. Attackers could…
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Medium 6.5
All versions of the package crow are vulnerable to HTTP Response Splitting when untrusted user input is used to build h…
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High 7.2
All versions of the package drogonframework/drogon are vulnerable to HTTP Response Splitting when untrusted user input …
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Medium 5.7
AMI SPx contains a vulnerability in the BMC where an Attacker may cause an improper neutralization of CRLF sequences in…
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Low 3.1
Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting') in GitLab
An issue has been discovered in GitLab CE/EE affecting all versions starting from 15.4 before 15.10.8, all versions starting from 15.11 before 15.11.7, all versions starting from 16.0 before 16.0.2. Open redirection was possible via HTTP response splitting in…
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High 7.2
HTTP Response Splitting via the ‘rest’ SPL Command
In Splunk Enterprise versions below 9.0.5, 8.2.11, and 8.1.14, and Splunk Cloud Platform versions below 9.0.2303.100, a low-privileged user can trigger an HTTP response splitting vulnerability with the ‘rest’ SPL command that lets them potentially access othe…
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Medium 4.0
A improper neutralization of crlf sequences in http headers ('http response splitting') vulnerability in Fortinet Forti…
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Medium 6.3
OnShift TurboGears HTTP Header controllers.py response splitting
A vulnerability classified as critical has been found in OnShift TurboGears 1.0.11.10. This affects an unknown part of the file turbogears/controllers.py of the component HTTP Header Handler. The manipulation leads to http response splitting. It is possible t…
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Medium 5.3CVE-2022-37436 EPSS 53%
Apache HTTP Server: mod_proxy prior to 2.4.55 allows a backend to trigger HTTP response splitting
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 …
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Medium 5.3
An improper neutralization of CRLF sequences in HTTP headers ('HTTP Response Splitting') vulnerability [CWE-113] In For…
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Medium 6.5
Netty vulnerable to HTTP Response splitting from assigning header value iterator
Netty project is an event-driven asynchronous network application framework. Starting in version 4.1.83.Final and prior to 4.1.86.Final, when calling `DefaultHttpHeadesr.set` with an _iterator_ of values, header value validation was not performed, allowing ma…
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Medium 4.7
A vulnerability in Cisco Email Security Appliance (ESA) and Cisco Secure Email and Web Manager could allow an unauthent…
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High 7.5
SwiftNIO vulnerable to Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Response Splitting')
NIOHTTP1 and projects using it for generating HTTP responses can be subject to a HTTP Response Injection attack. This occurs when a HTTP/1.1 server accepts user generated input from an incoming request and reflects it into a HTTP/1.1 response header in some f…
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Medium 4.7
WorkstationST - Response Splitting in AM Gateway Challenge-Response
An HTTP response splitting vulnerability exists in the AM Gateway Challenge-Response dialog of WorkstationST (<v07.09.15) and could allow an attacker to compromise a victim's browser/session. WorkstationST is only deployed in specific, controlled environments…
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Medium 5.0
HTTP Response Splitting in Hitachi Energy’s MSM Product
A vulnerability exists in the http web interface where the web interface does not validate data in an HTTP header. This causes a possible HTTP response splitting, which if exploited could lead an attacker to channel down harmful code into the user’s web brows…
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High 8.8
Junos OS: J-Web has an Improper Neutralization of CRLF Sequences in its HTTP Headers which allows an attacker to carry out multiple types of attacks.
An Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Response Splitting') weakness in J-web of Juniper Networks Junos OS leads to buffer overflows, segment faults, or other impacts, which allows an attacker to modify the integrity of the device…
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High 7.1
HTTP Response Splitting
This affects all versions of package github.com/gin-gonic/gin. When gin is exposed directly to the internet, a client's IP can be spoofed by setting the X-Forwarded-For header.
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Medium 4.7
Cisco Web Security Appliance and Cisco Content Security Management Appliance HTTP Header Injection Vulnerability
A vulnerability in the API Framework of Cisco AsyncOS for Cisco Web Security Appliance (WSA) and Cisco Content Security Management Appliance (SMA) could allow an unauthenticated, remote attacker to inject crafted HTTP headers in the web server's response. The…
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Medium 5.4
A flaw was found in the Red Hat Ceph Storage RadosGW (Ceph Object Gateway). The vulnerability is related to the injecti…
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Medium 6.5
HTTP Response Splitting (Early Hints) in Puma
In Puma (RubyGem) before 4.3.3 and 3.12.4, if an application using Puma allows untrusted input in an early-hints header, an attacker can use a carriage return character to end the header and inject malicious content, such as additional headers or an entirely …
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Medium 6.5
HTTP Response Splitting in Puma
In Puma (RubyGem) before 4.3.2 and before 3.12.3, if an application using Puma allows untrusted input in a response header, an attacker can use newline characters (i.e. `CR`, `LF` or`/r`, `/n`) to end the header and inject malicious content, such as additiona…
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Medium 6.5
HTTP Response Splitting in WSO2 transport-http
Netty in WSO2 transport-http before v6.3.1 is vulnerable to HTTP Response Splitting due to HTTP Header validation being disabled.
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Medium 4.4
Limited header injection when using dynamic overrides with user input in RubyGems secure_headers
In Secure Headers (RubyGem secure_headers), a directive injection vulnerability is present in versions before 3.9.0, 5.2.0, and 6.3.0. If user-supplied input was passed into append/override_content_security_policy_directives, a newline could be injected leadi…
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Medium 4.8
Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Response Splitting') in Armeria
Versions of Armeria 0.85.0 through and including 0.96.0 are vulnerable to HTTP response splitting, which allows remote attackers to inject arbitrary HTTP headers via CRLF sequences when unsanitized data is used to populate the headers of an HTTP response. Thi…
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Medium 6.1
Cisco Unified Contact Center Express HTTP Response Splitting Vulnerability
A vulnerability in Cisco Unified Contact Center Express (UCCX) Software could allow an unauthenticated, remote attacker to conduct an HTTP response splitting attack. The vulnerability is due to insufficient input validation of some parameters that are passed …
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Unscored —
A vulnerability has been identified in SIMATIC HMI Comfort Panels 4" - 22" (All versions < V14), SIMATIC HMI Comfort Ou…
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Medium 5.2
Ansible Tower as shipped with Red Hat CloudForms Management Engine 5 is vulnerable to CRLF Injection. It was found that…
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Medium 5.4
Improper Neutralization of CRLF Sequences in HTTP Headers in Undertow
In Undertow before versions 7.1.2.CR1, 7.1.2.GA it was found that the fix for CVE-2016-4993 was incomplete and Undertow web server is vulnerable to the injection of arbitrary HTTP headers, and also response splitting, due to insufficient sanitization and vali…
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Unscored —
A vulnerability in the web framework of Cisco Small Business Managed Switches software could allow an unauthenticated, …