Common Weakness Enumeration

CWE-79

Allowed

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Abstraction: Base · Status: Stable

API response cwe.mitre.org

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.

66868 vulnerabilities reference this CWE, most recent first.

GHSA-X4PW-5XX4-2JVJ

Vulnerability from github – Published: 2024-07-20 09:30 – Updated: 2024-07-20 09:30
VLAI
Details

Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting') vulnerability in iThemelandCo WooCommerce Report allows Reflected XSS.This issue affects WooCommerce Report: from n/a through 1.4.5.

Severity
7.1 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L
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{
  "affected": [],
  "aliases": [
    "CVE-2024-38683"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-07-20T08:15:07Z",
    "severity": "HIGH"
  },
  "details": "Improper Neutralization of Input During Web Page Generation (XSS or \u0027Cross-site Scripting\u0027) vulnerability in iThemelandCo WooCommerce Report allows Reflected XSS.This issue affects WooCommerce Report: from n/a through 1.4.5.",
  "id": "GHSA-x4pw-5xx4-2jvj",
  "modified": "2024-07-20T09:30:35Z",
  "published": "2024-07-20T09:30:35Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-38683"
    },
    {
      "type": "WEB",
      "url": "https://patchstack.com/database/vulnerability/ithemelandco-woo-report/wordpress-woocommerce-report-plugin-1-4-5-reflected-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-X4PX-49GQ-7FCJ

Vulnerability from github – Published: 2026-07-21 00:30 – Updated: 2026-07-21 18:30
VLAI
Details

Cross Site Scripting vulnerability in fuint Member Marketing System <=v1.0 allows a remote attacker to execute arbitrary code via the ClientMessageController.java file

Severity
6.1 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
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{
  "affected": [],
  "aliases": [
    "CVE-2026-51025"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-20T22:17:15Z",
    "severity": "MODERATE"
  },
  "details": "Cross Site Scripting vulnerability in fuint Member Marketing System \u003c=v1.0 allows a remote attacker to execute arbitrary code via the ClientMessageController.java file",
  "id": "GHSA-x4px-49gq-7fcj",
  "modified": "2026-07-21T18:30:55Z",
  "published": "2026-07-21T00:30:29Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-51025"
    },
    {
      "type": "WEB",
      "url": "https://github.com/W000i/vuln/issues/4"
    }
  ],
  "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:N",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-X4Q2-9Q8G-3MMF

Vulnerability from github – Published: 2022-05-24 19:19 – Updated: 2022-05-24 19:19
VLAI
Details

Certain HP Enterprise LaserJet and PageWide MFPs may be vulnerable to stored cross site scripting (XSS).

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{
  "affected": [],
  "aliases": [
    "CVE-2021-3662"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2021-10-29T12:15:00Z",
    "severity": "MODERATE"
  },
  "details": "Certain HP Enterprise LaserJet and PageWide MFPs may be vulnerable to stored cross site scripting (XSS).",
  "id": "GHSA-x4q2-9q8g-3mmf",
  "modified": "2022-05-24T19:19:14Z",
  "published": "2022-05-24T19:19:14Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-3662"
    },
    {
      "type": "WEB",
      "url": "https://support.hp.com/us-en/document/ish_4577473-4577502-16/hpsbpi03744"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

GHSA-X4Q2-HPMW-6W22

Vulnerability from github – Published: 2022-07-28 00:00 – Updated: 2026-07-05 00:31
VLAI
Details

A cross-site scripting (XSS) vulnerability in /index.php/?p=report of Online Fire Reporting System v1.0 allows attackers to execute arbitrary web scripts or HTML via a crafted payload injected into the "Contac #" text field.

Severity
5.4 (Medium)
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
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{
  "affected": [],
  "aliases": [
    "CVE-2022-34611"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2022-07-27T02:15:00Z",
    "severity": "MODERATE"
  },
  "details": "A cross-site scripting (XSS) vulnerability in /index.php/?p=report of Online Fire Reporting System v1.0 allows attackers to execute arbitrary web scripts or HTML via a crafted payload injected into the \"Contac #\" text field.",
  "id": "GHSA-x4q2-hpmw-6w22",
  "modified": "2026-07-05T00:31:34Z",
  "published": "2022-07-28T00:00:52Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2022-34611"
    },
    {
      "type": "WEB",
      "url": "https://github.com/As4ki/CVE-report/blob/main/OFRS.md"
    },
    {
      "type": "WEB",
      "url": "https://www.sourcecodester.com"
    },
    {
      "type": "WEB",
      "url": "http://online.com"
    }
  ],
  "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-X4Q4-7CPX-GG5V

Vulnerability from github – Published: 2022-05-24 17:44 – Updated: 2022-05-24 17:44
VLAI
Details

Unvalidated input and lack of output encoding in the WP Customer Reviews WordPress plugin, versions before 3.4.3, lead to multiple Stored Cross-Site Scripting vulnerabilities allowing remote attackers to inject arbitrary JavaScript code or HTML.

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{
  "affected": [],
  "aliases": [
    "CVE-2021-24135"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2021-03-18T15:15:00Z",
    "severity": "MODERATE"
  },
  "details": "Unvalidated input and lack of output encoding in the WP Customer Reviews WordPress plugin, versions before 3.4.3, lead to multiple Stored Cross-Site Scripting vulnerabilities allowing remote attackers to inject arbitrary JavaScript code or HTML.",
  "id": "GHSA-x4q4-7cpx-gg5v",
  "modified": "2022-05-24T17:44:49Z",
  "published": "2022-05-24T17:44:49Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-24135"
    },
    {
      "type": "WEB",
      "url": "https://wpscan.com/vulnerability/07e9e70b-97a6-42e3-b0de-8cb69dedcbd3"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

GHSA-X4Q5-6V5X-73CQ

Vulnerability from github – Published: 2022-05-17 02:40 – Updated: 2022-05-17 02:40
VLAI
Details

Cross-site scripting vulnerability in DERAEMON-CMS version 0.8.9 and earlier allows remote attackers to inject arbitrary web script or HTML via the parameters hostname, database and username.

Severity
6.1 (Medium)
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
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{
  "affected": [],
  "aliases": [
    "CVE-2016-7813"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2017-06-09T16:29:00Z",
    "severity": "MODERATE"
  },
  "details": "Cross-site scripting vulnerability in DERAEMON-CMS version 0.8.9 and earlier allows remote attackers to inject arbitrary web script or HTML via the parameters hostname, database and username.",
  "id": "GHSA-x4q5-6v5x-73cq",
  "modified": "2022-05-17T02:40:58Z",
  "published": "2022-05-17T02:40:58Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2016-7813"
    },
    {
      "type": "WEB",
      "url": "https://jvn.jp/en/jp/JVN75396659/index.html"
    },
    {
      "type": "WEB",
      "url": "http://emon-cms.com/new11"
    },
    {
      "type": "WEB",
      "url": "http://www.securityfocus.com/bid/94320"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-X4Q5-8J5G-HPJC

Vulnerability from github – Published: 2026-04-03 06:31 – Updated: 2026-04-04 06:50
VLAI
Summary
Roundcube Webmail: Insufficient HTML attachment sanitization in preview mode
Details

An issue was discovered in Roundcube Webmail before 1.5.14 and 1.6.14. XSS exists because of insufficient HTML attachment sanitization in preview mode. A victim must preview a text/html attachment.

Severity
6.1 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
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{
  "affected": [
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "roundcube/roundcubemail"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.7-beta"
            },
            {
              "fixed": "1.7-rc5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-35539"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-04-04T06:50:55Z",
    "nvd_published_at": "2026-04-03T05:16:21Z",
    "severity": "MODERATE"
  },
  "details": "An issue was discovered in Roundcube Webmail before 1.5.14 and 1.6.14. XSS exists because of insufficient HTML attachment sanitization in preview mode. A victim must preview a text/html attachment.",
  "id": "GHSA-x4q5-8j5g-hpjc",
  "modified": "2026-04-04T06:50:55Z",
  "published": "2026-04-03T06:31:32Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-35539"
    },
    {
      "type": "WEB",
      "url": "https://github.com/roundcube/roundcubemail/commit/10a6d1fa8acac85c727b0a6ae4a6642bfa27bea1"
    },
    {
      "type": "WEB",
      "url": "https://github.com/roundcube/roundcubemail/commit/1b30edf5369668c92fe91dae3d52e477c808aa4f"
    },
    {
      "type": "WEB",
      "url": "https://github.com/roundcube/roundcubemail/commit/d742954ccbcdee7020f8f2e7c49ce0fca5a0efab"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/roundcube/roundcubemail"
    },
    {
      "type": "WEB",
      "url": "https://github.com/roundcube/roundcubemail/releases/tag/1.5.14"
    },
    {
      "type": "WEB",
      "url": "https://github.com/roundcube/roundcubemail/releases/tag/1.6.14"
    },
    {
      "type": "WEB",
      "url": "https://github.com/roundcube/roundcubemail/releases/tag/1.7-rc5"
    },
    {
      "type": "WEB",
      "url": "https://roundcube.net/news/2026/03/18/security-updates-1.7-rc5-1.6.14-1.5.14"
    }
  ],
  "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:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Roundcube Webmail: Insufficient HTML attachment sanitization in preview mode"
}

GHSA-X4Q8-QXFW-MXFQ

Vulnerability from github – Published: 2022-05-17 03:39 – Updated: 2022-05-17 03:39
VLAI
Details

Cross-site scripting (XSS) vulnerability in the web-based management interface in Cisco Firepower Management Center before 6.1 and FireSIGHT System Software before 6.1 allows remote authenticated users to inject arbitrary web script or HTML via a crafted URL, aka Bug ID CSCuz58658.

Severity
5.4 (Medium)
CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
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{
  "affected": [],
  "aliases": [
    "CVE-2016-6395"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2016-09-12T10:59:00Z",
    "severity": "MODERATE"
  },
  "details": "Cross-site scripting (XSS) vulnerability in the web-based management interface in Cisco Firepower Management Center before 6.1 and FireSIGHT System Software before 6.1 allows remote authenticated users to inject arbitrary web script or HTML via a crafted URL, aka Bug ID CSCuz58658.",
  "id": "GHSA-x4q8-qxfw-mxfq",
  "modified": "2022-05-17T03:39:30Z",
  "published": "2022-05-17T03:39:30Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2016-6395"
    },
    {
      "type": "WEB",
      "url": "http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160907-fsss"
    },
    {
      "type": "WEB",
      "url": "http://www.securityfocus.com/bid/92824"
    },
    {
      "type": "WEB",
      "url": "http://www.securitytracker.com/id/1036755"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-X4QQ-4JC6-HR2V

Vulnerability from github – Published: 2022-05-17 04:39 – Updated: 2022-05-17 04:39
VLAI
Details

Cross-site scripting (XSS) vulnerability in share/pnp/application/views/kohana_error_page.php in PNP4Nagios before 0.6.22 allows remote attackers to inject arbitrary web script or HTML via a parameter that is not properly handled in an error message.

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{
  "affected": [],
  "aliases": [
    "CVE-2014-4907"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2014-07-11T11:08:00Z",
    "severity": "MODERATE"
  },
  "details": "Cross-site scripting (XSS) vulnerability in share/pnp/application/views/kohana_error_page.php in PNP4Nagios before 0.6.22 allows remote attackers to inject arbitrary web script or HTML via a parameter that is not properly handled in an error message.",
  "id": "GHSA-x4qq-4jc6-hr2v",
  "modified": "2022-05-17T04:39:47Z",
  "published": "2022-05-17T04:39:47Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2014-4907"
    },
    {
      "type": "WEB",
      "url": "https://bugs.op5.com/view.php?id=8761"
    },
    {
      "type": "WEB",
      "url": "http://docs.pnp4nagios.org/pnp-0.6/dwnld"
    },
    {
      "type": "WEB",
      "url": "http://openwall.com/lists/oss-security/2014/07/11/3"
    },
    {
      "type": "WEB",
      "url": "http://secunia.com/advisories/59535"
    },
    {
      "type": "WEB",
      "url": "http://secunia.com/advisories/59603"
    },
    {
      "type": "WEB",
      "url": "http://sourceforge.net/p/pnp4nagios/code/ci/f846a6c9d007ca2bee05359af747619151195fc9"
    },
    {
      "type": "WEB",
      "url": "http://www.op5.com/blog/news/op5-monitor-6-3-1-release-notes"
    },
    {
      "type": "WEB",
      "url": "http://www.securityfocus.com/bid/68350"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

GHSA-X4R7-M2Q9-69C8

Vulnerability from github – Published: 2021-11-08 18:03 – Updated: 2021-11-04 19:36
VLAI
Summary
GraphiQL introspection schema template injection attack
Details

This is a security advisory for an XSS vulnerability in graphiql.

A similar vulnerability affects graphql-playground, a fork of graphiql. There is a corresponding graphql-playground advisory and Apollo Server advisory.

1. Impact

All versions of graphiql older than graphiql@1.4.7 are vulnerable to compromised HTTP schema introspection responses or schema prop values with malicious GraphQL type names, exposing a dynamic XSS attack surface that can allow code injection on operation autocomplete.

In order for the attack to take place, the user must load a vulnerable schema in graphiql. There are a number of ways that can occur.

By default, the schema URL is not attacker-controllable in graphiql or in its suggested implementations or examples, leaving only very complex attack vectors.

If a custom implementation of graphiql's fetcher allows the schema URL to be set dynamically, such as a URL query parameter like ?endpoint= in graphql-playground, or a database provided value, then this custom graphiql implementation is vulnerable to phishing attacks, and thus much more readily available, low or no privelege level xss attacks. The URLs could look like any generic looking graphql schema URL.

Because this exposes an XSS attack surface, it would be possible for a threat actor to exfiltrate user credentials, data, etc. using arbitrary malicious scripts, without it being known to the user.

2. Scope

This advisory describes the impact on the graphiql package. The vulnerability also affects other projects forked from graphiql such as graphql-playground and the graphql-playground fork distributed by Apollo Server. The impact is more severe in the graphql-playground implementations; see the graphql-playground advisory and Apollo Server advisory for details.

This vulnerability does not impact codemirror-graphql, monaco-graphql or other dependents, as it exists in onHasCompletion.ts in graphiql. It does impact all forks of graphiql, and every released version of graphiql.

It should be noted that desktop clients such as Altair, Insomnia, Postwoman, do not appear to be impacted by this.

3. Patches

graphiql@1.4.7 addresses this issue via defense in depth.

  • HTML-escaping text that should be treated as text rather than HTML. In most of the app, this happens automatically because React escapes all interpolated text by default. However, one vulnerable component uses the unsafe innerHTML API and interpolated type names directly into HTML. We now properly escape that type name, which fixes the known vulnerability.

  • Validates the schema upon receiving the introspection response or schema changes. Schemas with names that violate the GraphQL spec will no longer be loaded. (This includes preventing the Doc Explorer from loading.) This change is also sufficient to fix the known vulnerability. You can disable this validation by setting dangerouslyAssumeSchemaIsValid={true}, which means you are relying only on escaping values to protect you from this attack.

  • Ensuring that user-generated HTML is safe. Schemas can contain Markdown in description and deprecationReason fields, and the web app renders them to HTML using the markdown-it library. As part of the development of graphiql@1.4.7, we verified that our use of markdown-it prevents the inclusion of arbitrary HTML. We use markdown-it without setting html: true, so we are comfortable relying on markdown-it's HTML escaping here. We considered running a second level of sanitization over all rendered Markdown using a library such as dompurify but believe that is unnecessary as markdown-it's sanitization appears to be adequate. graphiql@1.4.7 does update to the latest version of markdown-it (v12, from v10) so that any security fixes in v11 and v12 will take effect.

3.1 CDN bundle implementations may be automatically patched

Note that if your implementation is depending on a CDN version of graphiql, and is pointed to the latest tag (usually the default for most cdns if no version is specified) then this issue is already mitigated, in case you were vulnerable to it before.

4. Workarounds for Older Versions

If you cannot use graphiql@1.4.7 or later

  • Always use a static URL to a trusted server that is serving a trusted GraphQL schema.

  • If you have a custom implementation that allows using user-provided schema URLs via a query parameter, database value, etc, you must either disable this customization, or only allow trusted URLs.

5. How to Re-create the Exploit

You can see an example on codesandbox. These are both fixed to the last graphiql release 1.4.6 which is the last vulnerable release; however it would work with any previous release of graphiql.

Both of these examples are meant to demonstrate the phishing attack surface, so they are customized to accept a url parameter. To demonstrate the phishing attack, add ?url=https://graphql-xss-schema.netlify.app/graphql to the in-codesandbox browser.

Erase the contents of the given query and type {u. You will see an alert window open, showing that attacker-controlled code was executed.

Note that when React is in development mode, a validation exception is thrown visibly; however that exception is usually buried in the browser console in a production build of graphiql. This validation exception comes from getDiagnostics, which invokes graphql validate() which in turn will assertValidSchema(), as apollo-server-core does on executing each operation. This validation does not prevent the exploit from being successful.

Note that something like the url parameter is not required for the attack to happen if graphiql's fetcher is configured in a different way to communicate with a compromised GraphQL server.

6. Credit

This vulnerability was discovered by @Ry0taK, thank you! :1st_place_medal:

Others who contributed:

7. References

The vulnerability has always been present

In the first commit

And later moved to onHasCompletion.js in 2016 (now .ts after the typescript migration)

8. For more information

If you have any questions or comments about this advisory:

Severity
7.1 (High)
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:L
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{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "graphiql"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.5.0"
            },
            {
              "fixed": "1.4.7"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2021-41248"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2021-11-04T18:11:46Z",
    "nvd_published_at": "2021-11-04T21:15:00Z",
    "severity": "HIGH"
  },
  "details": "  - [1. Impact](#11-impact)\n  - [2. Scope](#12-scope)\n  - [3. Patches](#13-patches)\n    - [3.1 CDN bundle implementations may be automatically patched](#131-cdn-bundle-implementations-may-be-automatically-patched)\n  - [4. Workarounds for Older Versions](#14-workarounds-for-older-versions)\n  - [5. How to Re-create the Exploit](#15-how-to-re-create-the-exploit)\n  - [6. Credit](#16-credit)\n  - [7. References](#17-references)\n  - [8. For more information](#18-for-more-information)\n\nThis is a security advisory for an XSS vulnerability in `graphiql`.\n\nA similar vulnerability affects `graphql-playground`, a fork of `graphiql`. There is a corresponding `graphql-playground` [advisory](https://github.com/graphql/graphql-playground/security/advisories/GHSA-59r9-6jp6-jcm7) and [Apollo Server advisory](https://github.com/apollographql/apollo-server/security/advisories/GHSA-qm7x-rc44-rrqw).\n\n## 1. Impact\n\nAll versions of `graphiql` older than [`graphiql@1.4.7`](https://github.com/graphql/graphiql/releases/tag/v1.4.7) are vulnerable to compromised HTTP schema introspection responses or `schema` prop values with malicious GraphQL type names, exposing a dynamic XSS attack surface that can allow code injection on operation autocomplete.\n\nIn order for the attack to take place, the user must load a vulnerable schema in `graphiql`. There are a number of ways that can occur.\n\nBy default, the schema URL is _not_ attacker-controllable in `graphiql` or in its suggested implementations or examples, leaving only very complex attack vectors.\n\nIf a custom implementation of `graphiql`\u0027s `fetcher` allows the schema URL to be set dynamically, such as a URL query parameter like `?endpoint=` in `graphql-playground`, or a database provided value, then this custom `graphiql` implementation is _vulnerable to phishing attacks_, and thus much more readily available, low or no privelege level xss attacks. The URLs could look like any generic looking graphql schema URL.\n\nBecause this exposes an XSS attack surface, it would be possible for a threat actor to exfiltrate user credentials, data, etc. using arbitrary malicious scripts, without it being known to the user.\n\n## 2. Scope\n\nThis advisory describes the impact on the `graphiql` package. The vulnerability also affects other projects forked from `graphiql` such as [`graphql-playground`](https://github.com/graphql/graphql-playground/security/advisories/GHSA-59r9-6jp6-jcm7) and the `graphql-playground` fork distributed by Apollo Server. The impact is more severe in the `graphql-playground` implementations; see the [`graphql-playground` advisory](https://github.com/graphql/graphql-playground/security/advisories/GHSA-59r9-6jp6-jcm7) and [Apollo Server advisory](https://github.com/apollographql/apollo-server/security/advisories/GHSA-qm7x-rc44-rrqw) for details.\n\nThis vulnerability does not impact `codemirror-graphql`, `monaco-graphql` or other dependents, as it exists in `onHasCompletion.ts` in `graphiql`. It does impact all forks of `graphiql`, and every released version of `graphiql`.\n\nIt should be noted that desktop clients such as Altair, Insomnia, Postwoman, do not appear to be impacted by this.\n\n## 3. Patches\n\n`graphiql@1.4.7` addresses this issue via defense in depth.\n\n- **HTML-escaping text** that should be treated as text rather than HTML. In most of the app, this happens automatically because React escapes all interpolated text by default. However, one vulnerable component uses the unsafe `innerHTML` API and interpolated type names directly into HTML. We now properly escape that type name, which fixes the known vulnerability.\n\n- **Validates the schema** upon receiving the introspection response or schema changes. Schemas with names that violate the GraphQL spec will no longer be loaded. (This includes preventing the Doc Explorer from loading.) This change is also sufficient to fix the known vulnerability. You can disable this validation by setting `dangerouslyAssumeSchemaIsValid={true}`, which means you are relying only on escaping values to protect you from this attack.\n\n- **Ensuring that user-generated HTML is safe**. Schemas can contain Markdown in `description` and `deprecationReason` fields, and the web app renders them to HTML using the `markdown-it` library. As part of the development of `graphiql@1.4.7`, we verified that our use of `markdown-it` prevents the inclusion of arbitrary HTML. We use `markdown-it` without setting `html: true`, so we are comfortable relying on [`markdown-it`\u0027s HTML escaping](https://github.com/markdown-it/markdown-it/blob/master/docs/security.md) here. We considered running a second level of sanitization over all rendered Markdown using a library such as `dompurify` but believe that is unnecessary as `markdown-it`\u0027s sanitization appears to be adequate. `graphiql@1.4.7` does update to the latest version of `markdown-it` (v12, from v10) so that any security fixes in v11 and v12 will take effect.\n\n### 3.1 CDN bundle implementations may be automatically patched\n\nNote that if your implementation is depending on a CDN version of `graphiql`, and is pointed to the `latest` tag (usually the default for most cdns if no version is specified) then this issue is already mitigated, in case you were vulnerable to it before.\n\n## 4. Workarounds for Older Versions\n\nIf you cannot use `graphiql@1.4.7` or later\n\n- Always use a static URL to a trusted server that is serving a trusted GraphQL schema.\n\n- If you have a custom implementation that allows using user-provided schema URLs via a query parameter, database value, etc, you must either disable this customization, or only allow trusted URLs.\n\n## 5. How to Re-create the Exploit\n\nYou can see an example on [codesandbox](https://codesandbox.io/s/graphiql-xss-exploit-gr22f?file=/src/App.js). These are both fixed to the last `graphiql` release `1.4.6` which is the last vulnerable release; however it would work with any previous release of `graphiql`.\n\nBoth of these examples are meant to demonstrate the phishing attack surface, so they are customized to accept a `url` parameter. To demonstrate the phishing attack, add `?url=https://graphql-xss-schema.netlify.app/graphql` to the in-codesandbox browser.\n\nErase the contents of the given query and type `{u`. You will see an alert window open, showing that attacker-controlled code was executed.\n\nNote that when React is in development mode, a validation exception is thrown visibly; however that exception is usually buried in the browser console in a production build of `graphiql`. This validation exception comes from `getDiagnostics`, which invokes `graphql` `validate()` which in turn will `assertValidSchema()`, as `apollo-server-core` does on executing each operation. This validation does not prevent the exploit from being successful.\n\nNote that something like the `url` parameter is not required for the attack to happen if `graphiql`\u0027s `fetcher` is configured in a different way to communicate with a compromised GraphQL server.\n\n## 6. Credit\n\nThis vulnerability was discovered by [@Ry0taK](https://github.com/Ry0taK), thank you! :1st_place_medal:\n\nOthers who contributed:\n\n- [@imolorhe](https://github.com/imolorhe)\n- [@glasser](https://github.com/glasser)\n- [@divyenduz](https://github.com/divyenduz)\n- [@dotansimha](https://github.com/dotansimha)\n- [@acao](https://github.com/acao)\n- [@benjie](https://github.com/benjie) and many others who provided morale support\n\n## 7. References\n\n**The vulnerability has always been present**\n\n[In the first commit](https://github.com/graphql/graphiql/commit/b9dec272d89d9c590727fd10d62e4a47e0317fc7#diff-855b77f6310b7e4fb1bcac779cd945092ed49fd759f4684ea391b45101166437R87)\n\n[And later moved to onHasCompletion.js in 2016](https://github.com/graphql/graphiql/commit/6701b0b626e43800e32413590a295e5c1e3d5419#diff-d45eb76aebcffd27d3a123214487116fa95e0b5a11d70a94a0ce3033ce09f879R110) (now `.ts` after the typescript migration)\n\n## 8. For more information\n\nIf you have any questions or comments about this advisory:\n\n- Open an issue in [graphiql repo](https://github.com/graphql/graphiql/new/issues)\n- Read [more details](https://github.com/graphql/graphiql/blob/main/docs/security/2021-introspection-schema-xss.md#2-more-details-on-the-vulnerability) on the vulnerability",
  "id": "GHSA-x4r7-m2q9-69c8",
  "modified": "2021-11-04T19:36:52Z",
  "published": "2021-11-08T18:03:50Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/graphql/graphiql/security/advisories/GHSA-x4r7-m2q9-69c8"
    },
    {
      "type": "WEB",
      "url": "https://github.com/graphql/graphql-playground/security/advisories/GHSA-59r9-6jp6-jcm7"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-41248"
    },
    {
      "type": "WEB",
      "url": "https://github.com/graphql/graphiql/commit/6701b0b626e43800e32413590a295e5c1e3d5419#diff-d45eb76aebcffd27d3a123214487116fa95e0b5a11d70a94a0ce3033ce09f879R110"
    },
    {
      "type": "WEB",
      "url": "https://github.com/graphql/graphiql/commit/b9dec272d89d9c590727fd10d62e4a47e0317fc7#diff-855b77f6310b7e4fb1bcac779cd945092ed49fd759f4684ea391b45101166437R87"
    },
    {
      "type": "WEB",
      "url": "https://github.com/graphql/graphiql/commit/cb237eeeaf7333c4954c752122261db7520f7bf4"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/graphql/graphiql"
    },
    {
      "type": "WEB",
      "url": "https://github.com/graphql/graphiql/blob/main/docs/security/2021-introspection-schema-xss.md#2-more-details-on-the-vulnerability"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:L",
      "type": "CVSS_V3"
    }
  ],
  "summary": "GraphiQL introspection schema template injection attack"
}
Mitigation MIT-4
Architecture and Design

Strategy: Libraries or Frameworks

  • 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.
Mitigation
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:
  • 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.
  • HTML body
  • Element attributes (such as src="XYZ")
  • URIs
  • JavaScript sections
  • Cascading Style Sheets and style property
Mitigation MIT-6
Architecture and Design Implementation

Strategy: Attack Surface Reduction

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.

Mitigation MIT-15
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.

Mitigation MIT-27
Architecture and Design

Strategy: Parameterization

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.

Mitigation MIT-30.1
Implementation

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
Implementation

With Struts, write all data from form beans with the bean's filter attribute set to true.

Mitigation MIT-31
Implementation

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.

Mitigation MIT-5
Implementation

Strategy: Input Validation

  • Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
  • When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue."
  • Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
  • When dynamically constructing web pages, use stringent allowlists that limit the character set based on the expected value of the parameter in the request. All input should be validated and cleansed, 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. It is common to see 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.
  • Note that proper output encoding, escaping, and quoting is the most effective solution for preventing XSS, although input validation may provide some defense-in-depth. This is because it effectively limits what will appear in output. Input validation will not always prevent XSS, especially if you are required to support free-form text fields that could contain arbitrary characters. For example, in a chat application, the heart emoticon ("<3") would likely pass the validation step, since it is commonly used. However, it cannot be directly inserted into the web page because it contains the "<" character, which would need to be escaped or otherwise handled. In this case, stripping the "<" might reduce the risk of XSS, but it would produce incorrect behavior because the emoticon would not be recorded. This might seem to be a minor inconvenience, but it would be more important in a mathematical forum that wants to represent inequalities.
  • Even if you make a mistake in your validation (such as forgetting one out of 100 input fields), appropriate encoding is still likely to protect you from injection-based attacks. As long as it is not done in isolation, input validation is still a useful technique, since it may significantly reduce your attack surface, allow you to detect some attacks, and provide other security benefits that proper encoding does not address.
  • Ensure that you perform input validation at well-defined interfaces within the application. This will help protect the application even if a component is reused or moved elsewhere.
Mitigation MIT-21
Architecture and Design

Strategy: Enforcement by Conversion

When the set of acceptable objects, such as filenames or URLs, is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames or URLs, and reject all other inputs.

Mitigation MIT-29
Operation

Strategy: Firewall

Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth [REF-1481].

Mitigation MIT-16
Operation Implementation

Strategy: Environment Hardening

When using PHP, configure the application so that it does not use register_globals. During implementation, develop the application so that it does not rely on this feature, but be wary of implementing a register_globals emulation that is subject to weaknesses such as CWE-95, CWE-621, and similar issues.

CAPEC-209: XSS Using MIME Type Mismatch

An adversary creates a file with scripting content but where the specified MIME type of the file is such that scripting is not expected. The adversary tricks the victim into accessing a URL that responds with the script file. Some browsers will detect that the specified MIME type of the file does not match the actual type of its content and will automatically switch to using an interpreter for the real content type. If the browser does not invoke script filters before doing this, the adversary's script may run on the target unsanitized, possibly revealing the victim's cookies or executing arbitrary script in their browser.

CAPEC-588: DOM-Based XSS

This type of attack is a form of Cross-Site Scripting (XSS) where a malicious script is inserted into the client-side HTML being parsed by a web browser. Content served by a vulnerable web application includes script code used to manipulate the Document Object Model (DOM). This script code either does not properly validate input, or does not perform proper output encoding, thus creating an opportunity for an adversary to inject a malicious script launch a XSS attack. A key distinction between other XSS attacks and DOM-based attacks is that in other XSS attacks, the malicious script runs when the vulnerable web page is initially loaded, while a DOM-based attack executes sometime after the page loads. Another distinction of DOM-based attacks is that in some cases, the malicious script is never sent to the vulnerable web server at all. An attack like this is guaranteed to bypass any server-side filtering attempts to protect users.

CAPEC-591: Reflected XSS

This type of attack is a form of Cross-Site Scripting (XSS) where a malicious script is "reflected" off a vulnerable web application and then executed by a victim's browser. The process starts with an adversary delivering a malicious script to a victim and convincing the victim to send the script to the vulnerable web application.

CAPEC-592: Stored XSS

An adversary utilizes a form of Cross-site Scripting (XSS) where a malicious script is persistently "stored" within the data storage of a vulnerable web application as valid input.

CAPEC-63: Cross-Site Scripting (XSS)

An adversary embeds malicious scripts in content that will be served to web browsers. The goal of the attack is for the target software, the client-side browser, to execute the script with the users' privilege level. An attack of this type exploits a programs' vulnerabilities that are brought on by allowing remote hosts to execute code and scripts. Web browsers, for example, have some simple security controls in place, but if a remote attacker is allowed to execute scripts (through injecting them in to user-generated content like bulletin boards) then these controls may be bypassed. Further, these attacks are very difficult for an end user to detect.

CAPEC-85: AJAX Footprinting

This attack utilizes the frequent client-server roundtrips in Ajax conversation to scan a system. While Ajax does not open up new vulnerabilities per se, it does optimize them from an attacker point of view. A common first step for an attacker is to footprint the target environment to understand what attacks will work. Since footprinting relies on enumeration, the conversational pattern of rapid, multiple requests and responses that are typical in Ajax applications enable an attacker to look for many vulnerabilities, well-known ports, network locations and so on. The knowledge gained through Ajax fingerprinting can be used to support other attacks, such as XSS.

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