Weakness (CWE)
CWE-80: Improper Neutralization of Script-Related HTML Tags in a Web Page
The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes special characters such as "<", ">", and "&" that could be interpreted as web-scripting elements when they are sent to a downstream component that processes web pages.
How to prevent it (4 mitigations)
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Implementation
Carefully check each input parameter against a rigorous positive specification (allowlist) defining the specific characters and format allowed. All input should be neutralized, not just parameters that the user is supposed to specify, but all data in the request, including hidden fields, cookies, headers, the URL itself, and so forth. A common mistake that leads to continuing XSS vulnerabilities is to validate only fields that are expected to be redisplayed by the site. We often encounter data from the request that is reflected by the application server or the application that the development team did not anticipate. Also, a field that is not currently reflected may be used by a future developer. Therefore, validating ALL parts of the HTTP request is recommended.
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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.
The problem of inconsistent output encodings often arises in web pages. If an encoding is not specified in an HTTP header, web browsers often guess about which encoding is being used. This can open up the browser to subtle XSS attacks.
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Implementation
With Struts, write all data from form beans with the bean's filter attribute set to true.
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Implementation
To help mitigate XSS attacks against the user's session cookie, set the session cookie to be HttpOnly. In browsers that support the HttpOnly feature (such as more recent versions of Internet Explorer and Firefox), this attribute can prevent the user's session cookie from being accessible to malicious client-side scripts that use document.cookie. This is not a complete solution, since HttpOnly is not supported by all browsers. More importantly, XmlHttpRequest and other powerful browser technologies provide read access to HTTP headers, including the Set-Cookie header in which the HttpOnly flag is set.
Source: MITRE CWE-80
11 results · Clear filters · Feed
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Medium 6.1CVE-2026-52774 Public exploit
Reflected XSS via Unescaped `id` Parameter in Bazar Widget HTML Attributes in YesWiki
YesWiki is a wiki system written in PHP. Prior to version 4.6.6, YesWiki's Bazar widget handler reflects the id GET parameter into HTML attributes using strip_tags() only. Because strip_tags() does not escape double quotes, an attacker can break out of the at…
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Medium 6.1CVE-2026-50229 Public exploit
Apache Tomcat: XSS in number guess example
Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS) vulnerability in the number guess example for Apache Tomcat. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.22, from 10.1.0-M1 through 10.1.55, from 9.0.0.M1 through …
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Medium 6.1CVE-2026-41575 Public exploit
th30d4y/IP: DOM-Based Cross-Site Scripting (XSS) Vulnerability
In th30d4y/IP from version 1.0.1 to before version 2.0.1, a DOM-Based Cross-Site Scripting (XSS) vulnerability was identified in an IP Reputation Checker application. Unsanitized user input was directly rendered in the browser, allowing attackers to execute a…
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Medium 4.6CVE-2026-33657 Public exploit
EspoCRM: Stored HTML injection in email notifications about stream notes via unescaped post field
EspoCRM is an open source customer relationship management application. Versions 9.3.3 and below have a stored HTML injection vulnerability that allows any authenticated user with standard (non-administrative) privileges to inject arbitrary HTML into system-g…
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Medium 6.3CVE-2025-54589 Public exploit
copyparty Reflected XSS via Filter Parameter
Copyparty is a portable file server. In versions 1.18.6 and below, when accessing the recent uploads page at `/?ru`, users can filter the results using an input field at the top. This field appends a filter parameter to the URL, which reflects its value direc…
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Medium 6.4CVE-2025-4126 Public exploit
EG-Series <= 2.1.1 - Authenticated (Contributor+) Stored Cross-Site Scripting via Shortcode
The EG-Series plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the plugin's [series] shortcode in all versions up to, and including, 2.1.1 due to insufficient input sanitization and output escaping on user supplied attributes in the short…
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Medium 5.4CVE-2022-1274 Public exploit
HTML Injection in Keycloak Admin REST API
A flaw was found in Keycloak in the execute-actions-email endpoint. This issue allows arbitrary HTML to be injected into emails sent to Keycloak users and can be misused to perform phishing or other attacks against users.
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Medium 6.3
An issue was discovered in Roundcube Webmail before 1.3.12 and 1.4.x before 1.4.5. There is XSS via a malicious XML att…
KEV Jun 26, 2024 -
Medium 4.0CVE-2020-5267 Public exploit
Possible XSS vulnerability in ActionView
In ActionView before versions 6.0.2.2 and 5.2.4.2, there is a possible XSS vulnerability in ActionView's JavaScript literal escape helpers. Views that use the `j` or `escape_javascript` methods may be susceptible to XSS attacks. The issue is fixed in versions…
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Medium —
Apache Struts Cross-site scripting Vulnerability
Cross-site scripting (XSS) vulnerability in Apache Struts 1.2.7, and possibly other versions allows remote attackers to inject arbitrary web script or HTML via the query string, which is not properly quoted or filtered when the request handler generates an er…
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Medium —CVE-2002-1533 Public exploit
Jetty Javascript Inclusion Vulnerability
Cross-site scripting (XSS) vulnerability in Jetty JSP servlet engine allows remote attackers to insert arbitrary HTML or script via an HTTP request to a .jsp file whose name contains the malicious script and some encoded linefeed characters (%0a).