Weakness (CWE)
CWE-79: Cross-site Scripting
The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.
How to prevent it (8 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 [REF-1482].
Examples of libraries and frameworks that make it easier to generate properly encoded output include Microsoft's Anti-XSS library, the OWASP ESAPI Encoding module, and Apache Wicket.
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Implementation, Architecture and Design
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.
For any data that will be output to another web page, especially any data that was received from external inputs, use the appropriate encoding on all non-alphanumeric characters.
Parts of the same output document may require different encodings, which will vary depending on whether the output is in the:
- HTML body
- Element attributes (such as src="XYZ")
- URIs
- JavaScript sections
- Cascading Style Sheets and style property
etc. Note that HTML Entity Encoding is only appropriate for the HTML body.
Consult the XSS Prevention Cheat Sheet [REF-724] for more details on the types of encoding and escaping that are needed.
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Architecture and Design, Implementation
Understand all the potential areas where untrusted inputs can enter your software: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide data to the application. Remember that such inputs may be obtained indirectly through API calls.
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Architecture and Design
For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
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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.
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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-79
31 results · Clear filters · Feed
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High 8.1
Microsoft Exchange Server Spoofing Vulnerability
Improper neutralization of input during web page generation ('cross-site scripting') in Microsoft Exchange Server allows an unauthorized attacker to perform spoofing over a network.
KEV May 15, 2026 -
High 7.2
Zimbra Collaboration (ZCS) 10 before 10.0.18 and 10.1 before 10.1.13 allows Classic UI stored XSS via Cascading Style S…
KEV Mar 18, 2026 -
High 7.2
Roundcube Webmail before 1.5.12 and 1.6 before 1.6.12 is prone to a Cross-Site-Scripting (XSS) vulnerability via the an…
KEV Feb 20, 2026 -
Medium 6.1CVE-2025-48700 Exploited
An issue was discovered in Zimbra Collaboration (ZCS) 8.8.15 and 9.0 and 10.0 and 10.1. A Cross-Site Scripting (XSS) vu…
KEV Apr 20, 2026 -
Medium 5.4CVE-2025-27915 Exploited
An issue was discovered in Zimbra Collaboration (ZCS) 9.0 and 10.0 and 10.1. A stored cross-site scripting (XSS) vulner…
KEV Oct 7, 2025 -
Medium 6.3
A cookie management issue was addressed with improved state management. This issue is fixed in Safari 18.1.1, iOS 17.7.…
KEV Nov 21, 2024 -
Medium 5.3
Stored XSS vulnerability in MDaemon Email Server
An XSS issue was discovered in MDaemon Email Server before version 24.5.1c. An attacker can send an HTML e-mail message with JavaScript in an img tag. This could allow a remote attacker to load arbitrary JavaScript code in the context of a webmail user's brow…
KEV May 19, 2025 -
Medium 6.5
Windows MSHTML Platform Spoofing Vulnerability
Windows MSHTML Platform Spoofing Vulnerability
KEV Oct 8, 2024 -
Medium 6.1
An issue was discovered in Zimbra Collaboration (ZCS) 9.0 and 10.0. A Cross-Site Scripting (XSS) vulnerability exists i…
KEV May 19, 2025 -
Critical 9.3
A Cross-Site Scripting vulnerability in Roundcube through 1.5.7 and 1.6.x through 1.6.7 allows a remote attacker to ste…
KEV Jun 9, 2025 -
Medium 6.1
Roundcube Webmail before 1.5.7 and 1.6.x before 1.6.7 allows XSS via SVG animate attributes.
KEV Oct 24, 2024 -
Medium 6.1
Stored XSS vulnerability in Roundcube
Roundcube before 1.4.15, 1.5.x before 1.5.5, and 1.6.x before 1.6.4 allows stored XSS via an HTML e-mail message with a crafted SVG document because of program/lib/Roundcube/rcube_washtml.php behavior. This could allow a remote attacker to load arbitrary Java…
KEV Oct 26, 2023 -
Medium 6.1
Roundcube before 1.4.14, 1.5.x before 1.5.4, and 1.6.x before 1.6.3 allows XSS via text/plain e-mail messages with craf…
KEV Feb 12, 2024 -
Medium 6.1
Zimbra Collaboration (ZCS) 8 before 8.8.15 Patch 41 allows XSS in the Zimbra Classic Web Client.
KEV Jul 27, 2023 -
Critical 9.0
Cross Site Scripting vulnerability in Zimbra ZCS v.8.8.15 allows a remote authenticated attacker to execute arbitrary c…
KEV Feb 25, 2025 -
Medium 6.1
An XSS (Cross Site Scripting) vulnerability was found in HelpSystems Cobalt Strike through 4.7 that allowed a remote at…
KEV Mar 30, 2023 -
Medium 6.1
A reflected cross-site scripting (XSS) vulnerability in the /public/launchNewWindow.jsp component of Zimbra Collaborati…
KEV Apr 3, 2023 -
Medium 5.4
OpenPLC ScadaBR through 0.9.1 on Linux and through 1.12.4 on Windows allows stored XSS via system_settings.shtm.
KEV Nov 28, 2025 -
Medium 6.1CVE-2021-1879 Exploited
This issue was addressed by improved management of object lifetimes. This issue is fixed in iOS 12.5.2, iOS 14.4.2 and …
KEV Nov 3, 2021 -
Medium 6.1
An XSS issue was discovered in Roundcube Webmail before 1.2.13, 1.3.x before 1.3.16, and 1.4.x before 1.4.10. The attac…
KEV Jun 22, 2023 -
Medium 6.1
If exploited, this cross-site scripting vulnerability could allow remote attackers to inject malicious code. QNAP has a…
KEV May 24, 2022 -
High 8.0
If exploited, this cross-site scripting vulnerability could allow remote attackers to inject malicious code. QNAP has a…
KEV May 24, 2022 -
Medium 6.1
Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software Web Services Interface Cross-Site Scripting Vulnerabilities
Multiple vulnerabilities in the web services interface of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to conduct cross-site scripting (XSS) attacks against …
KEV Nov 3, 2021 -
Medium 6.9
Potential XSS vulnerability in jQuery
In jQuery versions greater than or equal to 1.0.3 and before 3.5.0, passing HTML containing <option> elements from untrusted sources - even after sanitizing it - to one of jQuery's DOM manipulation methods (i.e. .html(), .append(), and others) may execute unt…
KEV Jan 23, 2025 -
High 8.2
A vulnerability in WhatsApp Desktop versions prior to 0.3.9309 when paired with WhatsApp for iPhone versions prior to 2…
KEV May 23, 2022 -
Critical 9.8
The Crestron AM-100 firmware 1.6.0.2, Crestron AM-101 firmware 2.7.0.1, Barco wePresent WiPG-1000P firmware 2.3.0.10, B…
KEV Apr 15, 2022 -
Medium 6.1
The social-warfare plugin before 3.5.3 for WordPress has stored XSS via the wp-admin/admin-post.php?swp_debug=load_opti…
KEV Nov 3, 2021 -
Medium 6.1
Cross-site scripting (XSS) vulnerability in the ZmMailMsgView.getAttachmentLinkHtml function in Zimbra Collaboration Su…
KEV Apr 19, 2022 -
Medium 5.4
Cross-site scripting (XSS) vulnerability in the WebVPN login page in Cisco Adaptive Security Appliance (ASA) Software a…
KEV Nov 12, 2024 -
Medium 5.4
Multiple cross-site scripting (XSS) vulnerabilities in D-Link DSL-2760U Gateway (Rev. E1) allow remote authenticated us…
KEV Mar 25, 2022 -
Medium 6.1CVE-2012-0767 Exploited
Cross-site scripting (XSS) vulnerability in Adobe Flash Player before 10.3.183.15 and 11.x before 11.1.102.62 on Window…
KEV Jun 8, 2022