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
502 results · Feed
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High —
AWS SDK for .NET: Improper escaping of special characters in CloudFront policy document construction
### Summary This notification is related to the CloudFront signing utilities in the AWS SDK for .NET, which are used to generate Amazon CloudFront signed URLs and signed cookies. A defense-in-depth enhancement has been implemented to improve handling of speci…
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High 8.3
Handlebars.js has JavaScript Injection in CLI Precompiler via Unescaped Names and Options
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…
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High —
AWS SDK for Java 2.0: Improper Handling of Special Characters in CloudFront Signing Utilities
### Summary This notification is related to the [CloudFront signing utilities](https://github.com/aws/aws-sdk-java-v2/blob/master/services/cloudfront/src/main/java/software/amazon/awssdk/services/cloudfront/CloudFrontUtilities.java) in the AWS SDK for Java v2…
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Critical 9.4
OpenBao has Reflected XSS in its OIDC authentication error message
OpenBao is an open source identity-based secrets management system. Prior to version 2.5.2, OpenBao installations that have an OIDC/JWT authentication method enabled and a role with `callback_mode=direct` configured are vulnerable to XSS via the `error_descri…
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Low —
Loofah has improper detection of disallowed URIs via `allowed_uri?`
## Summary `Loofah::HTML5::Scrub.allowed_uri?` does not correctly reject `javascript:` URIs when the scheme is split by HTML entity-encoded control characters such as ` ` (carriage return), ` ` (line feed), or `	` (tab). ## Details The `allowed_uri…
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Medium 5.4
Invoice Ninja Denylist Bypass may Lead to Stored XSS via Invoice Line Items
Invoice Ninja is a source-available invoice, quote, project and time-tracking app built with Laravel. Invoice line item descriptions in Invoice Ninja v5.13.0 bypass the XSS denylist filter, allowing stored XSS payloads to execute when invoices are rendered in…
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Critical 9.3CVE-2026-32913 Public exploit
OpenClaw < 2026.3.7 - Custom Authorization Header Leakage via Cross-Origin Redirects
OpenClaw before 2026.3.7 contains an improper header validation vulnerability in fetchWithSsrFGuard that forwards custom authorization headers across cross-origin redirects. Attackers can trigger redirects to different origins to intercept sensitive headers l…
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Medium 6.1
Textpattern CMS 4.9.0: Second-Order XSS via Atom Feed Injection
Textpattern CMS version 4.9.0 contains a second-order cross-site scripting vulnerability that allows attackers to inject malicious scripts by exploiting improper sanitization of user-supplied input in Atom feed XML elements. Attackers can embed unescaped payl…
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High 8.2
Heimdall: Path received via Envoy gRPC corrupted when containing query string
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 expr…
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Medium 5.9
SuiteCRM has blind XSS in return_id parameter
SuiteCRM is an open-source, enterprise-ready Customer Relationship Management (CRM) software application. Prior to versions 7.15.1 and 8.9.3, the value of the return_id request parameter is copied into the value of an HTML tag attribute which is an event hand…
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Critical 9.3
FreeScout: Stored XSS via Unescaped Email Template Rendering ({!! $thread->body !!})
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 databas…
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High 7.1
OpenEMR has arbitrary image file read via PDF generator
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…
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High 7.1
OpenClaw < 2026.2.19 - Local Command Injection via Unsafe cmd Argument Handling in Windows Scheduled Task Script Generation
OpenClaw versions prior to 2026.2.19 contain a local command injection vulnerability in Windows scheduled task script generation due to unsafe handling of cmd metacharacters and expansion-sensitive characters in gateway.cmd files. Local attackers with control…
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High 8.1
jsPDF has a PDF Object Injection via FreeText color
jsPDF is a library to generate PDFs in JavaScript. Prior to version 4.2.1, user control of arguments of the `createAnnotation` method allows users to inject arbitrary PDF objects, such as JavaScript actions. If given the possibility to pass unsanitized input …
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Medium 6.9
LeafKit's HTML escaping may be skipped for Collection values, enabling XSS
LeafKit is a templating language with Swift-inspired syntax. Prior to version 1.14.2, HTML escaping doesn't work correctly when a template prints a collection (Array / Dictionary) via `#(value)`. This can result in XSS, allowing potentially untrusted input to…
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Medium 6.0
Incomplete control character validation in http.cookies
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_o…
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Medium 6.9
Craft has Reflective XSS via incomplete return URL sanitization
Craft is a content management system (CMS). The fix for CVE-2025-35939 in craftcms/cms introduced a strip_tags() call in src/web/User.php to sanitize return URLs before they are stored in the session. However, strip_tags() only removes HTML tags (angle bracke…
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Low 2.2
Improper Encoding or Escaping of Output in GitLab
GitLab has remediated an issue in GitLab CE/EE affecting all versions from 15.5 before 18.7.6, 18.8 before 18.8.6, and 18.9 before 18.9.2 that could have allowed an authenticated user with maintainer-role permissions to reveal Datadog API credentials under ce…
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Medium 6.1
lxml_html_clean: <base> tag injection through default Cleaner configuration
lxml_html_clean is a project for HTML cleaning functionalities copied from `lxml.html.clean`. Prior to version 0.4.4, the <base> tag passes through the default Cleaner configuration. While page_structure=True removes html, head, and title tags, there is no sp…
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Medium 6.1
lxml_html_clean: CSS @import Filter Bypass via Unicode Escapes
lxml_html_clean is a project for HTML cleaning functionalities copied from `lxml.html.clean`. Prior to version 0.4.4, the _has_sneaky_javascript() method strips backslashes before checking for dangerous CSS keywords. This causes CSS Unicode escape sequences t…
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High 8.6CVE-2025-66024 Public exploit
XWiki Blog Application home page vulnerable to Stored XSS via Post Title
The XWiki blog application allows users of the XWiki platform to create and manage blog posts. Versions starting with 9.15 and prior to 9.15.7 are vulnerable to Stored Cross-Site Scripting (XSS) via the Blog Post Title. The vulnerability arises because the po…
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High 8.0
Sub2API Vulnerable to Password Reset Poisoning via Host Header Trust Issue, Leading to Account Takeover
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…
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Medium 6.1
Vikunja has Reflected HTML Injection via filter Parameter in Projects Module
Vikunja is an open-source self-hosted task management platform. Prior to version 2.0.0, a reflected HTML injection vulnerability exists in the Projects module where the `filter` URL parameter is rendered into the DOM without output encoding when the user clic…
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Low 1.2
OpenEMR allows inconsistent escaping of translation function output
OpenEMR is a free and open source electronic health records and medical practice management application. Prior to version 8.0.0, the `xl()` translation function returns unescaped strings. While wrapper functions exist for escaping in different contexts (`xlt(…
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Medium 6.1
Tenda F3 Reflected Script Execution via Missing nosniff Header
Shenzhen Tenda F3 Wireless Router firmware V12.01.01.55_multi contains a content-type confusion vulnerability in the administrative interface. Responses omit the X-Content-Type-Options: nosniff header and include attacker-influenced content that can be reflec…
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Medium 6.1
Isso: Stored XSS via comment website field
Isso is a lightweight commenting server written in Python and JavaScript. In commits before 0afbfe0691ee237963e8fb0b2ee01c9e55ca2144, there is a stored Cross-Site Scripting (XSS) vulnerability affecting the website and author comment fields. The website field…
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High 8.9
OpenSift: Persistent XSS Chat Tool Rendering
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. Store…
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Medium 5.4
LibreNMS has Stored XSS in Custom OID - unit parameter missing strip_tags()
LibreNMS is an auto-discovering PHP/MySQL/SNMP based network monitoring tool. Versions 24.10.0 through 26.1.1 are vulnerable to Stored XSS via the unit parameter in Custom OID. The Custom OID functionality lacks strip_tags() sanitization while other fields (n…
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Medium 5.4
Pi-hole Web Interface has Stored HTML Injection via X-Forwarded-For Header in Active Sessions Table
Pi-hole Admin Interface is a web interface for managing Pi-hole, a network-level ad and internet tracker blocking application. Versions 6.0 and above have a Stored HTML Injection vulnerability in the active sessions table located on the API settings page, all…
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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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High 7.6
Fabric.js Affected by Stored XSS via SVG Export
Fabric.js is a Javascript HTML5 canvas library. Prior to version 7.2.0, Fabric.js applies `escapeXml()` to text content during SVG export (`src/shapes/Text/TextSVGExportMixin.ts:186`) but fails to apply it to other user-controlled string values that are inter…
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High 8.1CVE-2026-25940 Public exploit
jsPDF's PDF Injection in AcroForm module allows Arbitrary JavaScript Execution (RadioButton.createOption and "AS" property)
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 on…
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High 8.1CVE-2026-25755 Public exploit
jsPDF has PDF Object Injection via Unsanitized Input in addJS Method
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 deli…
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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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High 8.1
jsPDF has a PDF Injection in AcroFormChoiceField which allows Arbitrary JavaScript Execution
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 on…
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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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Low 2.1
Tenda W30E V2 Lacks X-Content-Type-Options Header
Shenzhen Tenda W30E V2 firmware versions up to and including V16.01.0.19(5037) fail to include the X-Content-Type-Options: nosniff response header on web management interfaces. As a result, browsers that perform MIME sniffing may incorrectly interpret attacke…