Weakness (CWE)
CWE-116: Improper Encoding or Escaping of Output
The product prepares a structured message for communication with another component, but encoding or escaping of the data is either missing or done incorrectly. As a result, the intended structure of the message is not preserved.
How to prevent it (7 mitigations)
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Architecture and Design
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
For example, consider using the ESAPI Encoding control [REF-45] or a similar tool, library, or framework. These will help the programmer encode outputs in a manner less prone to error.
Alternately, use built-in functions, but consider using wrappers in case those functions are discovered to have a vulnerability.
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Architecture and Design
If available, use structured mechanisms that automatically enforce the separation between data and code. These mechanisms may be able to provide the relevant quoting, encoding, and validation automatically, instead of relying on the developer to provide this capability at every point where output is generated.
For example, stored procedures can enforce database query structure and reduce the likelihood of SQL injection.
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Architecture and Design, Implementation
Understand the context in which your data will be used and the encoding that will be expected. This is especially important when transmitting data between different components, or when generating outputs that can contain multiple encodings at the same time, such as web pages or multi-part mail messages. Study all expected communication protocols and data representations to determine the required encoding strategies.
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Architecture and Design
In some cases, input validation may be an important strategy when output encoding is not a complete solution. For example, you may be providing the same output that will be processed by multiple consumers that use different encodings or representations. In other cases, you may be required to allow user-supplied input to contain control information, such as limited HTML tags that support formatting in a wiki or bulletin board. When this type of requirement must be met, use an extremely strict allowlist to limit which control sequences can be used. Verify that the resulting syntactic structure is what you expect. Use your normal encoding methods for the remainder of the input.
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Architecture and Design
Use input validation as a defense-in-depth measure to reduce the likelihood of output encoding errors (see CWE-20).
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Requirements
Fully specify which encodings are required by components that will be communicating with each other.
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Implementation
When exchanging data between components, ensure that both components are using the same character encoding. Ensure that the proper encoding is applied at each interface. Explicitly set the encoding you are using whenever the protocol allows you to do so.
Source: MITRE CWE-116
208 results · Clear filters · Feed
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Medium 5.4
Pi-hole Web Interface has Stored HTML Injection via Local DNS Records (CNAME/Hosts) in data-tag Attribute
Pi-hole Admin Interface is a web interface for managing Pi-hole, a network-level ad and internet tracker blocking application. Versions 6.4 and below are vulnerable to stored HTML injection through the local DNS records configuration page, which allows an aut…
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Medium 4.6
FileRise affected by HTML Injection using color property in file tags
FileRise is a self-hosted web file manager / WebDAV server. Prior to 3.3.0, an HTML Injection vulnerability allows an authenticated user to modify the DOM and add e.g. form elements that call certain endpoints or link elements that redirect the user on active…
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Medium 6.6
Tanium addressed an improper output sanitization vulnerability in TanOS.
Tanium addressed an improper output sanitization vulnerability in Tanium Appliance.
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Medium 6.3
HtmlSanitizer has a bypass via template tag
HtmlSanitizer is a .NET library for cleaning HTML fragments and documents from constructs that can lead to XSS attacks. Prior to versions 9.0.892 and 9.1.893-beta, if the template tag is allowed, its contents are not sanitized. The template tag is a special t…
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Medium 4.6
Discourse allows script execution in uploaded HTML/XML files on S3
Discourse is an open source discussion platform. A vulnerability present in versions prior to 3.5.4, 2025.11.2, 2025.12.1, and 2026.1.0 affects anyone who uses S3 for uploads. While scripts may be executed, they will only be run in the context of the S3/CDN d…
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Medium 4.3
CSS-based exfiltration of the content from partially encrypted emails when allowing remote content
When a user explicitly requested Thunderbird to decrypt an inline OpenPGP message that was embedded in a text section of an email that was formatted and styled with HTML and CSS, then the decrypted contents were rendered in a context in which the CSS styles f…
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Medium 5.4
Typemill has Reflected XSS via login error view template
Typemill is a flat-file, Markdown-based CMS designed for informational documentation websites. A reflected Cross-Site Scripting (XSS) exists in the login error view template `login.twig` of versions 2.19.1 and below. The `username` value can be echoed back wi…
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Medium 6.3
Docmost is vulnerable to stored Cross-Site Scripting (XSS) through Mermaid rendering
Docmost is open-source collaborative wiki and documentation software. In versions 0.3.0 through 0.23.2, Mermaid code block rendering is vulnerable to stored Cross-Site Scripting (XSS). The frontend can render attacker-controlled Mermaid diagrams using mermaid…
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Medium 6.1
Stored Cross-Site Scripting in Altium Live Support Center Comment Endpoint
A stored cross-site scripting (XSS) vulnerability exists in the Altium Support Center AddComment endpoint due to missing server-side input sanitization. Although the client interface applies HTML escaping, the backend accepts and stores arbitrary HTML and Jav…
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Medium 5.4
Server-Side Request Forgery (SSRF) in SAP BusinessObjects Business Intelligence Platform
SAP BusinessObjects Business Intelligence Platform lets an unauthenticated remote attacker send crafted requests through the URL parameter that controls the login page error message. This can cause the server to fetch attacker-supplied URLs, resulting in low …
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Medium 6.1
A DOM-based Cross-Site Scripting (XSS) vulnerability exists in the text editor feature of the Onlook web application 0.…
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Medium 5.1
Nagios XI < 5.8.6 Core Config Manager (CCM) Reflected XSS via Test Command
The Core Config Manager (CCM) in Nagios XI versions prior to CCM 3.1.4 / Nagios XI 5.8.6 contains a reflected cross-site scripting (XSS) vulnerability via the Test Command functionality. Insufficient validation or escaping of user-supplied input may allow an …
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Medium 5.3
DOS Vulnerability in ZTE MC889A Pro product
There is a Denial of Service（DoS）vulnerability in the ZTE MC889A Pro product. Due to insufficient validation of the input parameters of the Short Message Service interface, allowing an attacker to exploit it to carry out a DoS attack.
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Medium 6.1
An OBJECT tag type attribute overrode browser behavior on web resources without a content-type
A malicious page could have used the type attribute of an OBJECT tag to override the default browser behavior when encountering a web resource served without a content-type. This could have contributed to an XSS on a site that unsafely serves files without a …
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Medium 5.5
python-ldap Vulnerable to Improper Encoding or Escaping of Output and Improper Null Termination
python-ldap is a lightweight directory access protocol (LDAP) client API for Python. In versions prior to 3.4.5, ldap.dn.escape_dn_chars() escapes \x00 incorrectly by emitting a backslash followed by a literal NUL byte instead of the RFC-4514 hex form \00. An…
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Medium 4.3
HTML Injection in Logo Software's Logo Cloud
Improper Encoding or Escaping of Output vulnerability in Logo Software Inc. Logo Cloud allows Phishing. This issue affects Logo Cloud: before 2.57.
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Medium 5.9
Potential XSS in Extension:BlueSpiceWhoIsOnline
Improper Encoding or Escaping of Output vulnerability in Hallo Welt! GmbH BlueSpice (Extension:BlueSpiceWhoIsOnline) allows Cross-Site Scripting (XSS). This issue affects BlueSpice: from 5 through 5.1.1.
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Medium 5.9
Potential XSS in Extension:BlueSpiceAvatars
Improper Encoding or Escaping of Output vulnerability in Hallo Welt! GmbH BlueSpice (Extension:BlueSpiceAvatars) allows Cross-Site Scripting (XSS). This issue affects BlueSpice: from 5 through 5.1.1.
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Medium 5.9
Potential XSS in Extension:AtMentions
Improper Encoding or Escaping of Output vulnerability in Hallo Welt! GmbH BlueSpice (Extension:AtMentions) allows Cross-Site Scripting (XSS). This issue affects BlueSpice: from 5 through 5.1.1.
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Medium 4.3
HTML Injection in Patika Global Technologies' HumanSuite
Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting'), Improper Encoding or Escaping of Output, Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection') vulnerability in Patika Gl…
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Medium 6.4
Element Plus Link component (el-link) implements insufficient input validation for the href attribute
Element Plus Link component (el-link) through 2.10.6 implements insufficient input validation for the href attribute, creating a security abstraction gap that obscures URL-based attack vectors. The component passes user-controlled href values directly to unde…
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Medium 4.0
In multiple locations, there is a possible way to access content across user profiles due to URI double encoding. This …
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Medium 5.1
ETQ Reliance CG < SE.2025.1 Reflected XSS in `SQLConverterServlet`
A reflected cross-site scripting (XSS) vulnerability exists in ETQ Reliance CG (legacy) platform within the `SQLConverterServlet` component. This vulnerability requires user interaction, such as clicking a crafted link, and may result in execution of unauthor…
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Medium 6.5
Incorrect parsing of URLs could have allowed embedding of youtube.com
Firefox could have incorrectly parsed a URL and rewritten it to the youtube.com domain when parsing the URL specified in an `embed` tag. This could have bypassed website security checks that restricted which domains users were allowed to embed. This vulnerabi…
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Medium 4.9
IBM Security Guardium information disclosure
IBM Security Guardium 12.0 could allow a privileged user to download any file on the system due to improper escaping of input.
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Medium 6.5
Devtools' preview ignored CSP headers
Previewing a response in Devtools ignored CSP headers, which could have allowed content injection attacks. This vulnerability was fixed in Firefox 139 and Thunderbird 139.
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Medium 6.9
Yandex Browser for Android prior to version 21.3.0 allows remote attackers to perform IDN homograph attack.
Yandex Browser for Android prior to version 21.3.0 allows remote attackers to perform IDN homograph attack.
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Medium 5.8
YesWiki Remote Code Execution via Arbitrary PHP File Write and Execution
YesWiki is a wiki system written in PHP. Prior to version 4.5.4, YesWiki vulnerable to remote code execution. An arbitrary file write can be used to write a file with a PHP extension, which then can be browsed to in order to execute arbitrary code on the serv…
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Medium 5.7
Potential local code execution in "copy as cURL" command
Due to insufficient escaping of the special characters in the "copy as cURL" feature, an attacker could trick a user into using this command, potentially leading to local code execution on the user's system. *This bug only affects Firefox for Windows. Other v…
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Medium 4.2
Dell PowerProtect Data Manager Reporting, version(s) 19.17, 19.18 contain(s) an Improper Encoding or Escaping of Output…
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Medium 6.9
XSSes and potential RCE in Special:VersionCompare
Improper Encoding or Escaping of Output vulnerability in The Wikimedia Foundation Mediawiki - Version Compare Extension allows Cross-Site Scripting (XSS).This issue affects Mediawiki - Version Compare Extension: from 1.39 through 1.43.
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Medium 6.9
HTML injection in feed output from i18n message
Improper Encoding or Escaping of Output vulnerability in The Wikimedia Foundation Mediawiki Core - Feed Utils allows WebView Injection.This issue affects Mediawiki Core - Feed Utils: from 1.39 through 1.43.
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Medium 5.4
XSSes in Extension:ConfirmAccount
Improper Encoding or Escaping of Output vulnerability in The Wikimedia Foundation Mediawiki - Confirm Account Extension allows Cross-Site Scripting (XSS).This issue affects Mediawiki - Confirm Account Extension: from 1.39 through 1.43.
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Medium 5.3
Junos OS: Processing of a specific BGP update causes the SRRD process to crash
An Improper Encoding or Escaping of Output vulnerability in the Sampling Route Record Daemon (SRRD) of Juniper Networks Junos OS allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS). When a device configured for flow-monitoring…
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Medium 6.3
MathLive's Lack of Escaping of HTML allows for XSS
Cross Site Scripting vulnerability in arnog MathLive Versions v0.103.0 and before (fixed in 0.104.0) allows an attacker to execute arbitrary code via the MathLive function.
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Medium 5.3
Improper encoding or escaping of output vulnerability in the webapi component in Synology BeeStation OS (BSM) before 1.…
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Medium 5.3
WordPress Poll Maker Plugin < 5.5.5 - HTML Injection vulnerability
Improper Encoding or Escaping of Output vulnerability in Ays Pro Poll Maker poll-maker.This issue affects Poll Maker: from n/a through < 5.5.5.
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Medium 6.3
\htmlData does not validate attribute names in KaTeX
KaTeX is a fast, easy-to-use JavaScript library for TeX math rendering on the web. KaTeX users who render untrusted mathematical expressions with `renderToString` could encounter malicious input using `\htmlData` that runs arbitrary JavaScript, or generate in…
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Medium 4.0
Actionpack has possible cross-site scripting vulnerability via User Supplied Values to redirect_to
The redirect_to method in Rails allows provided values to contain characters which are not legal in an HTTP header value. This results in the potential for downstream services which enforce RFC compliance on HTTP response headers to remove the assigned Locati…
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Medium 5.4
Koji: escape html tag characters in the query string
A vulnerability in Koji was found. An unsanitized input allows for an XSS attack. Javascript code from a malicious link could be reflected in the resulting web page. It is not expected to be able to submit an action or make a change in Koji due to existing XS…