CWE-80
AllowedImproper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)
Abstraction: Variant · Status: Incomplete
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.
936 vulnerabilities reference this CWE, most recent first.
GHSA-QPRW-HC7P-66CJ
Vulnerability from github – Published: 2022-06-13 00:00 – Updated: 2022-06-22 00:00A vulnerability, which was classified as problematic, has been found in Thomson TCW710 ST5D.10.05. This issue affects some unknown processing of the file /goform/wlanPrimaryNetwork. The manipulation of the argument ServiceSetIdentifier with the input >alert(1) as part of POST Request leads to cross site scripting (Persistent). The attack may be initiated remotely. The exploit has been disclosed to the public and may be used.
{
"affected": [],
"aliases": [
"CVE-2018-25034"
],
"database_specific": {
"cwe_ids": [
"CWE-79",
"CWE-80"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2022-06-12T08:15:00Z",
"severity": "MODERATE"
},
"details": "A vulnerability, which was classified as problematic, has been found in Thomson TCW710 ST5D.10.05. This issue affects some unknown processing of the file /goform/wlanPrimaryNetwork. The manipulation of the argument ServiceSetIdentifier with the input \u003e\u003cscript\u003ealert(1)\u003c/script\u003e as part of POST Request leads to cross site scripting (Persistent). The attack may be initiated remotely. The exploit has been disclosed to the public and may be used.",
"id": "GHSA-qprw-hc7p-66cj",
"modified": "2022-06-22T00:00:57Z",
"published": "2022-06-13T00:00:19Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2018-25034"
},
{
"type": "WEB",
"url": "https://alquimistadesistemas.com/auditando-router-thomson-tcw710"
},
{
"type": "WEB",
"url": "https://vuldb.com/?ctiid.126695"
},
{
"type": "WEB",
"url": "https://vuldb.com/?id.126695"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N",
"type": "CVSS_V3"
}
]
}
GHSA-QQ8G-MC9V-7PV4
Vulnerability from github – Published: 2024-08-21 06:32 – Updated: 2024-08-21 06:32The Responsive video plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the plugin's video settings function in all versions up to, and including, 1.0 due to insufficient input sanitization and output escaping on user supplied attributes. This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This requires responsive videos to be enabled for posts.
{
"affected": [],
"aliases": [
"CVE-2024-7629"
],
"database_specific": {
"cwe_ids": [
"CWE-79",
"CWE-80"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-08-21T06:15:12Z",
"severity": "MODERATE"
},
"details": "The Responsive video plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the plugin\u0027s video settings function in all versions up to, and including, 1.0 due to insufficient input sanitization and output escaping on user supplied attributes. This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This requires responsive videos to be enabled for posts.",
"id": "GHSA-qq8g-mc9v-7pv4",
"modified": "2024-08-21T06:32:19Z",
"published": "2024-08-21T06:32:19Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-7629"
},
{
"type": "WEB",
"url": "https://plugins.trac.wordpress.org/browser/responsive-video/trunk/responsive-video.php#L534"
},
{
"type": "WEB",
"url": "https://www.wordfence.com/threat-intel/vulnerabilities/id/c530f5d2-eed3-433b-bf96-656593ad6ce2?source=cve"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N",
"type": "CVSS_V3"
}
]
}
GHSA-QR2H-WJ83-58JC
Vulnerability from github – Published: 2023-10-11 18:30 – Updated: 2025-11-04 21:30A stored cross-site scripting (XSS) vulnerability exists in the upload_brand.cgi functionality of peplink Surf SOHO HW1 v6.3.5 (in QEMU). A specially crafted HTTP request can lead to execution of arbitrary javascript in another user's browser. An attacker can make an authenticated HTTP request to trigger this vulnerability.
{
"affected": [],
"aliases": [
"CVE-2023-34354"
],
"database_specific": {
"cwe_ids": [
"CWE-79",
"CWE-80"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2023-10-11T16:15:13Z",
"severity": "MODERATE"
},
"details": "A stored cross-site scripting (XSS) vulnerability exists in the upload_brand.cgi functionality of peplink Surf SOHO HW1 v6.3.5 (in QEMU). A specially crafted HTTP request can lead to execution of arbitrary javascript in another user\u0027s browser. An attacker can make an authenticated HTTP request to trigger this vulnerability.",
"id": "GHSA-qr2h-wj83-58jc",
"modified": "2025-11-04T21:30:44Z",
"published": "2023-10-11T18:30:39Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-34354"
},
{
"type": "WEB",
"url": "https://talosintelligence.com/vulnerability_reports/TALOS-2023-1781"
},
{
"type": "WEB",
"url": "https://www.talosintelligence.com/vulnerability_reports/TALOS-2023-1781"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:N/A:N",
"type": "CVSS_V3"
}
]
}
GHSA-QV4X-V2V4-F8P9
Vulnerability from github – Published: 2024-02-22 06:30 – Updated: 2024-08-30 14:42Withdrawn Advisory
This advisory has been withdrawn because the vendor reports that some HTML formatting (such as with an H1 element) is allowed, but there is backend sanitization such that the reporter's mentioned "injecting malicious scripts" would not occur.
Original Advisory
An HTML injection vulnerability in the Edit Content Layout module of Kirby CMS v4.1.0 allows attackers to execute arbitrary code via a crafted payload.
{
"affected": [
{
"package": {
"ecosystem": "Packagist",
"name": "getkirby/cms"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"last_affected": "4.1.0"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2024-26482"
],
"database_specific": {
"cwe_ids": [
"CWE-80"
],
"github_reviewed": true,
"github_reviewed_at": "2024-02-26T22:15:36Z",
"nvd_published_at": "2024-02-22T05:15:09Z",
"severity": "HIGH"
},
"details": "## Withdrawn Advisory\nThis advisory has been withdrawn because the vendor reports that some HTML formatting (such as with an H1 element) is allowed, but there is backend sanitization such that the reporter\u0027s mentioned \"injecting malicious scripts\" would not occur.\n\n## Original Advisory\nAn HTML injection vulnerability in the Edit Content Layout module of Kirby CMS v4.1.0 allows attackers to execute arbitrary code via a crafted payload.",
"id": "GHSA-qv4x-v2v4-f8p9",
"modified": "2024-08-30T14:42:28Z",
"published": "2024-02-22T06:30:33Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-26482"
},
{
"type": "PACKAGE",
"url": "https://github.com/getkirby/kirby"
},
{
"type": "WEB",
"url": "https://shrouded-trowel-50c.notion.site/Kirby-CMS-4-1-0-HTML-Injection-19ca19686d0a4533ab4b0c53fc977eef?pvs=4"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H",
"type": "CVSS_V3"
}
],
"summary": "Withdrawn Advisory: Kirby CMS HTML injection vulnerability",
"withdrawn": "2024-08-30T14:42:28Z"
}
GHSA-QV6C-367R-3W6Q
Vulnerability from github – Published: 2022-12-02 22:26 – Updated: 2024-11-22 20:34Impact
XSS Vulnerability in multiple XBlock Fields. Any platform that has deployed the XBlock will be impacted.
Patches
https://github.com/openedx/xblock-drag-and-drop-v2/commit/53c4482f9bb6d8c7ccdf5253bd82c84a222b2492
The fix is compatible with all Open edX releases newer than Lilac.
Workarounds
None.
References
https://github.com/openedx/xblock-drag-and-drop-v2/pull/295#issuecomment-1277693864
{
"affected": [
{
"package": {
"ecosystem": "PyPI",
"name": "xblock-drag-and-drop-v2"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "3.0.0"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2022-46147"
],
"database_specific": {
"cwe_ids": [
"CWE-79",
"CWE-80"
],
"github_reviewed": true,
"github_reviewed_at": "2022-12-02T22:26:22Z",
"nvd_published_at": "2022-11-28T21:15:00Z",
"severity": "HIGH"
},
"details": "### Impact\nXSS Vulnerability in multiple XBlock Fields. Any platform that has deployed the XBlock will be impacted.\n\n### Patches\nhttps://github.com/openedx/xblock-drag-and-drop-v2/commit/53c4482f9bb6d8c7ccdf5253bd82c84a222b2492\n\nThe fix is compatible with all Open edX releases newer than Lilac.\n\n### Workarounds\nNone.\n\n### References\nhttps://github.com/openedx/xblock-drag-and-drop-v2/pull/295#issuecomment-1277693864\n",
"id": "GHSA-qv6c-367r-3w6q",
"modified": "2024-11-22T20:34:30Z",
"published": "2022-12-02T22:26:22Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/openedx/xblock-drag-and-drop-v2/security/advisories/GHSA-qv6c-367r-3w6q"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2022-46147"
},
{
"type": "WEB",
"url": "https://github.com/openedx/xblock-drag-and-drop-v2/pull/295#issuecomment-1277693864"
},
{
"type": "WEB",
"url": "https://github.com/openedx/xblock-drag-and-drop-v2/commit/53c4482f9bb6d8c7ccdf5253bd82c84a222b2492"
},
{
"type": "WEB",
"url": "https://github.com/openedx/xblock-drag-and-drop-v2/commit/68887d1b4a44325d2de7573d450e41129ba98b1a"
},
{
"type": "PACKAGE",
"url": "https://github.com/openedx/xblock-drag-and-drop-v2"
},
{
"type": "WEB",
"url": "https://github.com/openedx/xblock-drag-and-drop-v2/releases/tag/v3.0.0"
},
{
"type": "WEB",
"url": "https://github.com/pypa/advisory-database/tree/main/vulns/xblock-drag-and-drop-v2/PYSEC-2022-43175.yaml"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:H",
"type": "CVSS_V3"
}
],
"summary": "XBlock vulnerable to Cross-Site Scripting (XSS) "
}
GHSA-QXVP-MR53-FP4V
Vulnerability from github – Published: 2024-01-17 18:31 – Updated: 2024-01-17 18:31A vulnerability in the web-based management interface of Cisco Prime Infrastructure could allow an authenticated, remote attacker to conduct cross-site scripting attacks. This vulnerability is due to improper validation of user-supplied input to the web-based management interface. An attacker could exploit this vulnerability by submitting malicious input containing script or HTML content within requests that would stored within the application interface. A successful exploit could allow the attacker to conduct cross-site scripting attacks against other users of the affected application.
{
"affected": [],
"aliases": [
"CVE-2023-20257"
],
"database_specific": {
"cwe_ids": [
"CWE-79",
"CWE-80"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-01-17T17:15:09Z",
"severity": "MODERATE"
},
"details": "A vulnerability in the web-based management interface of Cisco Prime Infrastructure could allow an authenticated, remote attacker to conduct cross-site scripting attacks. This vulnerability is due to improper validation of user-supplied input to the web-based management interface. An attacker could exploit this vulnerability by submitting malicious input containing script or HTML content within requests that would stored within the application interface. A successful exploit could allow the attacker to conduct cross-site scripting attacks against other users of the affected application.",
"id": "GHSA-qxvp-mr53-fp4v",
"modified": "2024-01-17T18:31:38Z",
"published": "2024-01-17T18:31:38Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-20257"
},
{
"type": "WEB",
"url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-pi-epnm-wkZJeyeq"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N",
"type": "CVSS_V3"
}
]
}
GHSA-R299-G8PG-6XF2
Vulnerability from github – Published: 2025-03-28 15:31 – Updated: 2026-04-01 18:34Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS) vulnerability in Improve My City Improve My City allows Reflected XSS. This issue affects Improve My City: from n/a through 1.6.
{
"affected": [],
"aliases": [
"CVE-2025-22501"
],
"database_specific": {
"cwe_ids": [
"CWE-80"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-03-28T15:15:46Z",
"severity": "HIGH"
},
"details": "Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS) vulnerability in Improve My City Improve My City allows Reflected XSS. This issue affects Improve My City: from n/a through 1.6.",
"id": "GHSA-r299-g8pg-6xf2",
"modified": "2026-04-01T18:34:14Z",
"published": "2025-03-28T15:31:57Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-22501"
},
{
"type": "WEB",
"url": "https://patchstack.com/database/wordpress/plugin/improve-my-city/vulnerability/wordpress-improve-my-city-plugin-1-6-cross-site-scripting-xss-vulnerability?_s_id=cve"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L",
"type": "CVSS_V3"
}
]
}
GHSA-R29H-37FJ-X2W6
Vulnerability from github – Published: 2026-05-14 20:21 – Updated: 2026-05-19 15:59Summary
There is a Cross-Site Scripting vulnerability in Open WebUI SVG renderer implementation.
Details
It is possible permanently save any HTML/JavaScript code in the application, which can be then executed in the context of the application domain. This behaviour can be used to extract and steal sensitive data from the application, manipulate DOM tree or being used in complex client-side attacks.
Detailed step-by-step instruction provided below. Please keep me updated about assigned CVE identifier. I'd like to be credited as: Jakub Żoczek [Securitum]
PoC
Steps to reproduce:
To reproduce this vulnerability you need to:
- Login to Open WebUI
- Start new conversation / thread
- Use prompt: "Hey. Can you draw me a green circle using SVG ?"
- SVG image should be generated.
- Now it's possible to edit the code by simply clicking on it and adding additional code. Add payload
<img src=a onerror=alert(document.domain)> - The whole code should look like this:
<svg width="100" height="100" xmlns="http://www.w3.org/2000/svg">
<circle cx="50" cy="50" r="40" fill="green"/>
</svg><img src="a" onerror="alert(document.domain)">ok</img>
- Now clicking "Save", the new image should get rendered, and malicious code - executed (by popping alert).
Such thread could be then shared and sent to other users.
Impact
Cross-Site Scripting allows attacker to execute malicious code in context of victim's browser. This way it could be used in malicious client-side attack achieving different things, depends on attacker's goal. Such thread with rendered SVG could be shared to other user (or administrator) and gain sensitive data or even takeover someone's account.
{
"affected": [
{
"package": {
"ecosystem": "npm",
"name": "open-webui"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "0.6.31"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-45346"
],
"database_specific": {
"cwe_ids": [
"CWE-80"
],
"github_reviewed": true,
"github_reviewed_at": "2026-05-14T20:21:51Z",
"nvd_published_at": "2026-05-15T22:16:55Z",
"severity": "MODERATE"
},
"details": "### Summary\nThere is a Cross-Site Scripting vulnerability in Open WebUI SVG renderer implementation. \n\n### Details\n\nIt is possible permanently save any HTML/JavaScript code in the application, which can be then executed in the context of the application domain. This behaviour can be used to extract and steal sensitive data from the application, manipulate DOM tree or being used in complex client-side attacks. \n\nDetailed step-by-step instruction provided below. Please keep me updated about assigned CVE identifier. I\u0027d like to be credited as: **Jakub \u017boczek [[Securitum](https://www.securitum.com/)]**\n\n### PoC\n\nSteps to reproduce:\n\nTo reproduce this vulnerability you need to:\n\n1. Login to Open WebUI \n2. Start new conversation / thread\n3. Use prompt: \"Hey. Can you draw me a green circle using SVG ?\"\n4. SVG image should be generated. \n5. Now it\u0027s possible to edit the code by simply clicking on it and adding additional code. Add payload `\u003cimg src=a onerror=alert(document.domain)\u003e`\n6. The whole code should look like this:\n\n```\n\u003csvg width=\"100\" height=\"100\" xmlns=\"http://www.w3.org/2000/svg\"\u003e\n \u003ccircle cx=\"50\" cy=\"50\" r=\"40\" fill=\"green\"/\u003e\n\u003c/svg\u003e\u003cimg src=\"a\" onerror=\"alert(document.domain)\"\u003eok\u003c/img\u003e\n```\n\n\u003cimg width=\"1249\" alt=\"AI XSS1\" src=\"https://github.com/user-attachments/assets/75167880-79ac-4510-9743-f99bf81a215d\" /\u003e\n\n7. Now clicking \"Save\", the new image should get rendered, and malicious code - executed (by popping alert). \n\n\u003cimg width=\"527\" alt=\"AI XSS2\" src=\"https://github.com/user-attachments/assets/24d4e572-97f0-438f-993d-08e1d421b349\" /\u003e\n\nSuch thread could be then shared and sent to other users. \n\n### Impact\nCross-Site Scripting allows attacker to execute malicious code in context of victim\u0027s browser. This way it could be used in malicious client-side attack achieving different things, depends on attacker\u0027s goal. Such thread with rendered SVG could be shared to other user (or administrator) and gain sensitive data or even takeover someone\u0027s account.",
"id": "GHSA-r29h-37fj-x2w6",
"modified": "2026-05-19T15:59:41Z",
"published": "2026-05-14T20:21:51Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/open-webui/open-webui/security/advisories/GHSA-r29h-37fj-x2w6"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-45346"
},
{
"type": "PACKAGE",
"url": "https://github.com/open-webui/open-webui"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N",
"type": "CVSS_V4"
}
],
"summary": "Open WebUI Has Stored Cross-Site Scripting in SVG Renderer"
}
GHSA-R398-VW7Q-9J92
Vulnerability from github – Published: 2025-03-17 21:30 – Updated: 2025-03-19 21:30Code-projects Online Class and Exam Scheduling System V1.0 is vulnerable to Cross Site Scripting (XSS) in profile.php via the member_first and member_last parameters.
{
"affected": [],
"aliases": [
"CVE-2025-29427"
],
"database_specific": {
"cwe_ids": [
"CWE-80"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-03-17T19:15:27Z",
"severity": "MODERATE"
},
"details": "Code-projects Online Class and Exam Scheduling System V1.0 is vulnerable to Cross Site Scripting (XSS) in profile.php via the member_first and member_last parameters.",
"id": "GHSA-r398-vw7q-9j92",
"modified": "2025-03-19T21:30:51Z",
"published": "2025-03-17T21:30:34Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-29427"
},
{
"type": "WEB",
"url": "https://github.com/872323857/CVE/blob/main/Online%20Class%20and%20Exam%20Scheduling%20System-profile.pdf"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:L/A:L",
"type": "CVSS_V3"
}
]
}
GHSA-R49W-9HVC-8FG7
Vulnerability from github – Published: 2024-11-06 18:31 – Updated: 2024-11-06 18:31A vulnerability in the web-based management interface of Cisco AsyncOS Software for Cisco Secure Email and Web Manager, Secure Email Gateway, and Secure Web Appliance could allow an authenticated, remote attacker to conduct a stored cross-site scripting (XSS) attack against a user of the interface.
This vulnerability is due to insufficient validation of user input. An attacker could exploit this vulnerability by persuading a user of an affected interface to click a crafted link. A successful exploit could allow the attacker to execute arbitrary script code in the context of the affected interface or access sensitive, browser-based information.
{
"affected": [],
"aliases": [
"CVE-2024-20504"
],
"database_specific": {
"cwe_ids": [
"CWE-80"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-11-06T17:15:16Z",
"severity": "MODERATE"
},
"details": "A vulnerability in the web-based management interface of Cisco AsyncOS Software for Cisco Secure Email and Web Manager, Secure Email Gateway, and Secure Web Appliance could allow an authenticated, remote attacker to conduct a stored cross-site scripting (XSS) attack against a user of the interface.\n\nThis vulnerability is due to insufficient validation of user input. An attacker could exploit this vulnerability by persuading a user of an affected interface to click a crafted link. A successful exploit could allow the attacker to execute arbitrary script code in the context of the affected interface or access sensitive, browser-based information.",
"id": "GHSA-r49w-9hvc-8fg7",
"modified": "2024-11-06T18:31:11Z",
"published": "2024-11-06T18:31:11Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-20504"
},
{
"type": "WEB",
"url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-esa-wsa-sma-xss-zYm3f49n"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N",
"type": "CVSS_V3"
}
]
}
Mitigation
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.
Mitigation MIT-30.1
Strategy: Output Encoding
- 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.
Mitigation MIT-43
With Struts, write all data from form beans with the bean's filter attribute set to true.
Mitigation MIT-31
Strategy: Attack Surface Reduction
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.
CAPEC-18: XSS Targeting Non-Script Elements
This attack is a form of Cross-Site Scripting (XSS) where malicious scripts are embedded in elements that are not expected to host scripts such as image tags (<img>), comments in XML documents (< !-CDATA->), etc. These tags may not be subject to the same input validation, output validation, and other content filtering and checking routines, so this can create an opportunity for an adversary to tunnel through the application's elements and launch a XSS attack through other elements. As with all remote attacks, it is important to differentiate the ability to launch an attack (such as probing an internal network for unpatched servers) and the ability of the remote adversary to collect and interpret the output of said attack.
CAPEC-193: PHP Remote File Inclusion
In this pattern the adversary is able to load and execute arbitrary code remotely available from the application. This is usually accomplished through an insecurely configured PHP runtime environment and an improperly sanitized "include" or "require" call, which the user can then control to point to any web-accessible file. This allows adversaries to hijack the targeted application and force it to execute their own instructions.
CAPEC-32: XSS Through HTTP Query Strings
An adversary embeds malicious script code in the parameters of an HTTP query string and convinces a victim to submit the HTTP request that contains the query string to a vulnerable web application. The web application then procedes to use the values parameters without properly validation them first and generates the HTML code that will be executed by the victim's browser.
CAPEC-86: XSS Through HTTP Headers
An adversary exploits web applications that generate web content, such as links in a HTML page, based on unvalidated or improperly validated data submitted by other actors. XSS in HTTP Headers attacks target the HTTP headers which are hidden from most users and may not be validated by web applications.