Improper Encoding or Escaping of Output
CWE-116
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.
We track 193 vulnerabilities of this type. 99% are rated high or critical, and the average CVSS score is 8.5. 4 have been exploited in real attacks.
How this weakness is prevented
- 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 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.
- 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.
- 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.
- Architecture and Design: Use input validation as a defense-in-depth measure to reduce the likelihood of output encoding errors (see CWE-20).
- Requirements: Fully specify which encodings are required by components that will be communicating with each other.
Latest Improper Encoding or Escaping of Output vulnerabilities
- 8.1 High severity
The issue was addressed with improved input validation.
The issue was addressed with improved input validation. This issue is fixed in Safari 26.5, iOS 18.7.9 and iPadOS 18.7.9, iOS 26.5 and iPadOS 26.5, macOS Tahoe 26.5, tvOS 26.5, visionOS 26.5, watchOS 26.5. Processing maliciously crafted web content may prevent
- 9.9 Critical severity
Apache Polaris accepts literal `*` characters in namespace and table names.
Apache Polaris accepts literal `*` characters in namespace and table names. When it later builds temporary S3 access policies for delegated table access, those same characters appear to be reused unescaped in S3 IAM resource patterns and `s3:prefix` conditions
- 7.2 High severity
mailcow: dockerized is an open source groupware/email suite based on docker.
mailcow: dockerized is an open source groupware/email suite based on docker. Versions prior to 2026-03b have a second-order SQL injection vulnerability in the quarantine_category field via the Mailcow API. The /api/v1/add/mailbox endpoint stores quarantine_cat
- 8.5 High severity
freescout: Improper Neutralization of Input During Web Page Generation
FreeScout is a free self-hosted help desk and shared mailbox. Versions prior to 1.8.213 have a stored cross-site scripting (XSS) vulnerability in the mailbox signature feature. The sanitization function `Helper::stripDangerousTags()` (`app/Misc/Helper.php:568`
- 8.8 High severity
emissary: Improper Neutralization of Special Elements used in an OS Command
Emissary is a P2P based data-driven workflow engine. In versions 8.42.0 and below, Executrix.getCommand() is vulnerable to OS command injection because it interpolates temporary file paths into a /bin/sh -c shell command string without any escaping or input va
- 8.7 High severity
apostrophe: Improper Neutralization of Input During Web Page Generation
ApostropheCMS is an open-source Node.js content management system. Versions 4.28.0 and prior contain a stored cross-site scripting vulnerability in SEO-related fields (SEO Title and Meta Description), where user-controlled input is rendered without proper outp
- 7.5 High severity
Apache Log4j JSON Template Layout: Improper Encoding or Escaping of Output
Apache Log4j's JsonTemplateLayout https://logging.apache.org/log4j/2.x/manual/json-template-layout.html , in versions up to and including 2.25.3, produces invalid JSON output when log events contain non-finite floating-point values (NaN, Infinity, or -Infinity
- 7.5 High severity
Apache Log4j Core: Improper Encoding or Escaping of Output
Apache Log4j Core's XmlLayout https://logging.apache.org/log4j/2.x/manual/layouts.html#XmlLayout , in versions up to and including 2.25.3, fails to sanitize characters forbidden by the XML 1.0 specification https://www.w3.org/TR/xml/#charsets producing invalid
- 7.5 High severity
Apache Log4j 1 to Log4j 2 bridge: Improper Encoding or Escaping of Output
The Log4j1XmlLayout from the Apache Log4j 1-to-Log4j 2 bridge fails to escape characters forbidden by the XML 1.0 standard, producing malformed XML output. Conforming XML parsers are required to reject documents containing such characters with a fatal error, w
- 7.5 High severity
Apache Tomcat: Improper Encoding or Escaping of Output
Improper Encoding or Escaping of Output vulnerability in the JsonAccessLogValve component of Apache Tomcat. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.20, from 10.1.0-M1 through 10.1.53, from 9.0.40 through 9.0.116. Users are recommended to
- 7.6 High severity
CRM: Improper Neutralization of Input During Web Page Generation
ChurchCRM is an open-source church management system. Prior to 7.1.0, a stored cross-site scripting vulnerability exists in PersonView.php due to incorrect use of sanitizeText() as an output sanitizer for HTML attribute context. The function only strips HTML t
- 8.2 High severity
handlebars.js: Improper Neutralization of Input During Web Page Generation
Handlebars provides the power necessary to let users build semantic templates. In versions 4.0.0 through 4.7.8, the Handlebars CLI precompiler (`bin/handlebars` / `lib/precompiler.js`) concatenates user-controlled strings — template file names and several CLI
- 7.5 High severity
heimdall: Improper Encoding or Escaping of Output
Heimdall is a cloud native Identity Aware Proxy and Access Control Decision service. When using Heimdall in envoy gRPC decision API mode with versions 0.7.0-alpha through 0.17.10, wrong encoding of the query URL string allows rules with non-wildcard path expre
- 9.3 Critical severity
freescout: Improper Neutralization of Input During Web Page Generation
FreeScout is a free help desk and shared inbox built with PHP's Laravel framework. Versions 1.8.208 and below are vulnerable to Stored Cross-Site Scripting (XSS) through FreeScout's email notification templates. Incoming email bodies are stored in the database
- 8.1 High severity
openemr: Improper Encoding or Escaping of Output
OpenEMR is a free and open source electronic health records and medical practice management application. Prior to 8.0.0.2, users with the `Notes - my encounters` role can fill Eye Exam forms in patient encounters. The answers to the form can be printed out in
- 7.5 High severity
The fix for CVE-2026-0672, which rejected control characters in http.cookies.Morsel, was…
The fix for CVE-2026-0672, which rejected control characters in http.cookies.Morsel, was incomplete. The Morsel.update(), |= operator, and unpickling paths were not patched, allowing control characters to bypass input validation. Additionally, BaseCookie.js_ou
- 9.1 Critical severity
sub2api: Improper Encoding or Escaping of Output
Sub2API is an AI API gateway platform designed to distribute and manage API quotas from AI product subscriptions. A vulnerability in versions prior to 0.1.85 is a Password Reset Poisoning (Host Header / Forwarded Header trust issue), which allows attackers to
- 8.9 High severity
OpenSift: Improper Neutralization of Input During Web Page Generation
OpenSift is an AI study tool that sifts through large datasets using semantic search and generative AI. Versions 1.1.2-alpha and below render untrusted user/model content in chat tool UI surfaces using unsafe HTML interpolation patterns, leading to XSS. Stored
- 8.1 High severity
jsPDF: Improper Encoding or Escaping of Output
jsPDF is a library to generate PDFs in JavaScript. Prior to 4.2.0, user control of properties and methods of the Acroform module allows users to inject arbitrary PDF objects, such as JavaScript actions. If given the possibility to pass unsanitized input to one
- 8.8 High severity
jsPDF: Improper Control of Generation of Code
jsPDF is a library to generate PDFs in JavaScript. Prior to 4.2.0, user control of the argument of the `addJS` method allows an attacker to inject arbitrary PDF objects into the generated document. By crafting a payload that escapes the JavaScript string delim
- 8.1 High severity
jsPDF: Improper Encoding or Escaping of Output
jsPDF is a library to generate PDFs in JavaScript. Prior to 4.1.0, user control of properties and methods of the Acroform module allows users to inject arbitrary PDF objects, such as JavaScript actions. If given the possibility to pass unsanitized input to one
- 9.6 Critical severity
5ire: Improper Encoding or Escaping of Output
5ire is a cross-platform desktop artificial intelligence assistant and model context protocol client. Prior to version 0.15.3, an unsafe HTML rendering permits untrusted HTML (including on* event attributes) to execute in the renderer context. An attacker can
- 7.3 High severity
OnboardLite is a comprehensive membership lifecycle platform built for student organizations…
OnboardLite is a comprehensive membership lifecycle platform built for student organizations at the University of Central Florida. Versions of the software prior to commit 1d32081a66f21bcf41df1ecb672490b13f6e429f have a stored cross-site scripting vulnerabilit
- 8.0 High severity
coolify: Improper Neutralization of Input During Web Page Generation
Coolify is an open-source and self-hostable tool for managing servers, applications, and databases. Coolify versions prior to and including v4.0.0-beta.420.6 are vulnerable to a stored cross-site scripting (XSS) attack in the project creation workflow. An auth
- 7.7 High severity
GitLab: Improper Encoding or Escaping of Output
GitLab has remediated a security issue in GitLab CE/EE affecting all versions from 17.1 before 18.4.6, 18.5 before 18.5.4, and 18.6 before 18.6.2 that could have allowed an authenticated user to perform unauthorized actions on behalf of other users by injectin
- 9.0 Critical severity
Emby.Security: Improper Neutralization of Input During Web Page Generation
Emby Server is a personal media server. Prior to version 4.8.1.0 and prior to Beta version 4.9.0.0-beta, a malicious user can send an authentication request with a manipulated X-Emby-Client value, which gets added to the devices section of the admin dashboard
- 9.1 Critical severity
Serv-U: Improper Encoding or Escaping of Output
A logic error vulnerability exists in Serv-U which when abused could give a malicious actor with access to admin privileges the ability to execute code. This issue requires administrative privileges to abuse. On Windows deployments, the risk is scored as a med
- 8.6 High severity
FactoryTalk® DataMosaix™ Private Cloud: Improper Encoding or Escaping of Output
A security issue exists within DataMosaix™ Private Cloud allowing for Persistent XSS. This vulnerability can result in the execution of malicious JavaScript, allowing for account takeover, credential theft, or redirection to a malicious website.
- 8.1 High severity
Firefox: Improper Encoding or Escaping of Output
Insufficient escaping in the “Copy as cURL” feature could have been used to trick a user into executing unexpected code on Windows. This did not affect the application when running on other operating systems. This vulnerability was fixed in Firefox 144, Firefo
- 8.1 High severity
pyload: Improper Neutralization of Special Elements in Output Used by a Downstream Component
pyLoad is a free and open-source download manager written in Python. In versions prior to 0.5.0b3.dev91, pyLoad web interface contained insufficient input validation in both the Captcha script endpoint and the Click'N'Load (CNL) Blueprint. This flaw allowed un
- 7.2 High severity
MotionEye v0.43.1b4 and before is vulnerable to OS Command Injection in configuration…
MotionEye v0.43.1b4 and before is vulnerable to OS Command Injection in configuration parameters such as image_file_name. Unsanitized user input is written to Motion configuration files, allowing remote authenticated attackers with admin access to achieve code
- 9.4 Critical severity
get-jwks: Improper Encoding or Escaping of Output
get-jwks contains fetch utils for JWKS keys. In versions prior to 11.0.2, a vulnerability in get-jwks can lead to cache poisoning in the JWKS key-fetching mechanism. When the iss (issuer) claim is validated only after keys are retrieved from the cache, it is p
- 10.0 Critical severity
xwiki-pro-macros: Improper Encoding or Escaping of Output
XWiki Remote Macros provides XWiki rendering macros that are useful when migrating content from Confluence. Starting in version 1.0 and prior to version 1.26.5, missing escaping of the title in the confluence paste code macro allows remote code execution for a
- 10.0 Critical severity
xwiki-pro-macros: Improper Encoding or Escaping of Output
XWiki Remote Macros provides XWiki rendering macros that are useful when migrating content from Confluence. Starting in version 1.0 and prior to version 1.26.5, missing escaping of the ac:type in the ConfluenceLayoutSection macro allows remote code execution f
- 9.9 Critical severity
WilderForge: Improper Control of Generation of Code
WilderForge is a Wildermyth coremodding API. A critical vulnerability has been identified in multiple projects across the WilderForge organization. The issue arises from unsafe usage of `${{ github.event.review.body }}` and other user controlled variables dire
- 7.5 High severity
Niagara Framework: Improper Encoding or Escaping of Output
Improper Output Neutralization for Logs vulnerability in Tridium Niagara Framework on Windows, Linux, QNX, Tridium Niagara Enterprise Security on Windows, Linux, QNX allows Input Data Manipulation. This issue affects Niagara Framework: before 4.14.2, before 4.
- 9.1 Critical severity
Cloud Waf: Improper Encoding or Escaping of Output
Radware Cloud Web Application Firewall (WAF) before 2025-05-07 allows remote attackers to bypass firewall filters by adding a special character to the request.
- 9.0 Critical severity
xwiki-platform: Improper Encoding or Escaping of Output
XWiki is a generic wiki platform. In versions starting from 15.9-rc-1 to before 15.10.8 and from 16.0.0-rc-1 to before 16.2.0, the required rights analysis doesn't consider TextAreas with default content type. When editing a page, XWiki warns since version 15.
- 7.1 High severity
ctrlX OS - Solutions: Improper Encoding or Escaping of Output
A vulnerability in the “Manages app data” functionality of the web application of ctrlX OS allows a remote authenticated (lowprivileged) attacker to execute arbitrary client-side code in the context of another user's browser via multiple crafted HTTP requests.
- 9.8 Critical severity
yeswiki: Improper Encoding or Escaping of Output
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 serve