{"id":"CVE-2023-45818","aliases":["CLSA-2026-1777423184","EUVD-2023-2813","GHSA-5vm8-hhgr-jcjp","GHSA-v65r-p3vv-jjfv","UBUNTU-CVE-2023-45818"],"status":"published","title":"Cross-site Scripting vulnerability in TinyMCE undo/redo, getContent API, resetContent API, and Autosave plugin","description":"TinyMCE is an open source rich text editor. A mutation cross-site scripting (mXSS) vulnerability was discovered in TinyMCE’s core undo and redo functionality. When a carefully-crafted HTML snippet passes the XSS sanitisation layer, it is manipulated as a string by internal trimming functions before being stored in the undo stack. If the HTML snippet is restored from the undo stack, the combination of the string manipulation and reparative parsing by either the browser's native [DOMParser API](https://developer.mozilla.org/en-US/docs/Web/API/DOMParser) (TinyMCE 6) or the SaxParser API (TinyMCE 5) mutates the HTML maliciously, allowing an XSS payload to be executed. This vulnerability has been patched in TinyMCE 5.10.8 and TinyMCE 6.7.1 by ensuring HTML is trimmed using node-level manipulation instead of string manipulation. Users are advised to upgrade. There are no known workarounds for this vulnerability.","severity":{"version":"3.1","score":6.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.00759,"percentile":0.55547,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-79"],"published":"2021-05-28T19:18:53Z","modified":"2026-10-28T02:30:56Z","fixes":[{"ecosystem":"npm","package":"tinymce","fixed_in":["5.7.1","6.7.1","5.10.8"],"sources":["ghsa","osv"]},{"ecosystem":"NuGet","package":"TinyMCE","fixed_in":["6.7.1","5.10.8"],"sources":["ghsa","osv"]},{"ecosystem":"Packagist","package":"tinymce/tinymce","fixed_in":["6.7.1","5.10.8"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"npm","package":"tinymce","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"5.7.1"}]}]},{"source":"ghsa","ecosystem":"npm","package":"tinymce","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.0.0"},{"fixed":"6.7.1"}]}]},{"source":"ghsa","ecosystem":"NuGet","package":"TinyMCE","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.0.0"},{"fixed":"6.7.1"}]}]},{"source":"ghsa","ecosystem":"Packagist","package":"tinymce/tinymce","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.0.0"},{"fixed":"6.7.1"}]}]},{"source":"ghsa","ecosystem":"npm","package":"tinymce","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"5.10.8"}]}]},{"source":"ghsa","ecosystem":"NuGet","package":"TinyMCE","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"5.10.8"}]}]},{"source":"ghsa","ecosystem":"Packagist","package":"tinymce/tinymce","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"5.10.8"}]}]},{"source":"osv","ecosystem":"TuxCare:npm","package":"tinymce","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.9.11-tuxcare.0"},{"fixed":"4.9.11-tuxcare.1"}]}],"versions":["4.9.11"],"bundled":11},{"source":"osv","ecosystem":"npm","package":"tinymce","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"5.7.1"}]}]},{"source":"osv","ecosystem":"npm","package":"tinymce","ranges":[{"type":"SEMVER","events":[{"introduced":"6.0.0"},{"fixed":"6.7.1"}]}]},{"source":"osv","ecosystem":"NuGet","package":"TinyMCE","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.0.0"},{"fixed":"6.7.1"}]}],"versions":["6.0.0","6.0.1","6.0.2","6.0.3","6.1.0","6.1.1","6.1.2","6.2.0","6.3.0","6.3.1","6.3.2","6.4.0","6.4.1","6.4.2","6.5.0","6.5.1","6.6.2","6.7.0"]},{"source":"osv","ecosystem":"Packagist","package":"tinymce/tinymce","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.0.0"},{"fixed":"6.7.1"}]}],"versions":["6.0.0","6.0.1","6.0.2","6.0.3","6.1.0","6.1.1","6.1.2","6.2.0","6.3.0","6.3.1","6.3.2","6.4.0","6.4.1","6.4.2","6.5.0","6.5.1","6.6.0","6.6.1","6.6.2","6.7.0"]},{"source":"osv","ecosystem":"npm","package":"tinymce","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"5.10.8"}]}]},{"source":"osv","ecosystem":"NuGet","package":"TinyMCE","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"5.10.8"}]}],"versions":["3.4.3.2","3.4.4","3.4.5","3.4.7","3.5.0","3.5.0.1","3.5.1","3.5.1.1","3.5.2","3.5.3","3.5.4","3.5.4.1","3.5.5","3.5.6","3.5.7","3.5.8","4.0.0","4.0.1","4.0.10","4.0.11","4.0.13","4.0.14","4.0.15","4.0.16","4.0.17","4.0.18","4.0.19","4.0.2","4.0.20","4.0.21","4.0.22","4.0.23","4.0.24","4.0.25","4.0.26","4.0.27","4.0.28","4.0.4","4.0.5","4.0.6","4.0.8","4.0.9","4.1.0","4.1.1","4.1.10","4.1.2","4.1.3","4.1.4","4.1.5","4.1.6","4.1.7","4.1.8","4.1.9","4.2.0","4.2.1","4.2.2","4.2.3","4.2.4","4.2.5","4.2.6","4.2.7","4.2.8","4.3.0","4.3.1","4.3.10","4.3.11","4.3.12","4.3.13","4.3.2","4.3.3","4.3.4","4.3.6","4.3.7","4.3.8","4.3.9","4.4.0","4.4.1","4.4.2","4.4.3","4.5.0","4.5.1","4.5.2","4.5.3","4.5.4","4.5.5","4.5.6","4.5.7","4.5.8","4.6.0","4.6.1","4.6.2","4.6.3","4.6.4","4.6.5","4.6.6","4.6.7","4.7.0","4.7.10","4.7.11","4.7.12","4.7.13","4.7.3","4.7.4","4.7.5","4.7.6","4.7.7","4.7.8","4.7.9","4.8.0","4.8.1","4.8.2","4.8.3","4.8.4","4.8.5","4.9.0","4.9.1","4.9.10","4.9.11","4.9.2","4.9.3","4.9.4","4.9.5","4.9.6","4.9.7","4.9.8","4.9.9","5.0.0","5.0.1","5.0.10","5.0.11","5.0.12","5.0.13","5.0.14","5.0.15","5.0.16","5.0.2","5.0.3","5.0.4","5.0.5","5.0.6","5.0.7","5.0.8","5.0.9","5.1.0","5.1.1","5.1.2","5.1.3","5.1.4","5.1.5","5.1.6","5.10.0","5.10.1","5.10.2","5.10.3","5.10.4","5.10.5","5.10.6","5.10.7","5.2.0","5.2.1","5.2.2","5.3.0","5.3.1","5.3.2","5.4.0","5.4.1","5.4.2","5.5.0","5.5.1","5.6.0","5.6.1","5.6.2","5.7.0","5.7.1","5.8.0","5.8.1","5.8.2","5.9.0","5.9.1","5.9.2"]},{"source":"osv","ecosystem":"Packagist","package":"tinymce/tinymce","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"5.10.8"}]}],"versions":["4.0.0","4.0.1","4.0.10","4.0.11","4.0.12","4.0.13","4.0.14","4.0.15","4.0.16","4.0.17","4.0.18","4.0.19","4.0.2","4.0.20","4.0.21","4.0.22","4.0.23","4.0.24","4.0.25","4.0.26","4.0.27","4.0.28","4.0.3","4.0.4"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Advisory","advisory","web","report"]},{"url":"https://researchgate.net/publication/266654651_mXSS_attacks_Attacking_well-secured_web-applications_by_using_innerHTML_mutations","tags":["x_refsource_MISC","x_transferred","Third Party Advisory","web","report"]},{"url":"https://tiny.cloud/docs/release-notes/release-notes5108/#securityfixes","tags":["x_refsource_MISC","x_transferred","Release Notes","web","report"]},{"url":"https://tiny.cloud/docs/tinymce/6/6.7.1-release-notes/#security-fixes","tags":["x_refsource_MISC","x_transferred","Release Notes","web","report"]},{"url":"https://www.tiny.cloud/docs/api/tinymce.html/tinymce.html.saxparser/","tags":["x_refsource_MISC","x_transferred","Product","web","report"]},{"url":"https://github.com/tinymce/tinymce/security/advisories/GHSA-5vm8-hhgr-jcjp","tags":["web"]},{"url":"https://github.com/advisories/GHSA-5vm8-hhgr-jcjp"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2023-45818","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-v65r-p3vv-jjfv"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/45xxx/CVE-2023-45818.json","tags":["advisory"]},{"url":"https://github.com/tinymce/tinymce","tags":["package"]},{"url":"https://www.tiny.cloud/docs/api/tinymce.html/tinymce.html.saxparser","tags":["web"]},{"url":"https://ubuntu.com/security/CVE-2023-45818","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2023-45818","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2023-45818","title":"Cross-site Scripting vulnerability in TinyMCE undo/redo, getContent API, resetContent API, and Autosave plugin","description":"TinyMCE is an open source rich text editor. A mutation cross-site scripting (mXSS) vulnerability was discovered in TinyMCE’s core undo and redo functionality. When a carefully-crafted HTML snippet passes the XSS sanitisation layer, it is manipulated as a string by internal trimming functions before being stored in the undo stack. If the HTML snippet is restored from the undo stack, the combination of the string manipulation and reparative parsing by either the browser's native [DOMParser API](https://developer.mozilla.org/en-US/docs/Web/API/DOMParser) (TinyMCE 6) or the SaxParser API (TinyMCE 5) mutates the HTML maliciously, allowing an XSS payload to be executed. This vulnerability has been patched in TinyMCE 5.10.8 and TinyMCE 6.7.1 by ensuring HTML is trimmed using node-level manipulation instead of string manipulation. Users are advised to upgrade. There are no known workarounds for this vulnerability.","status":"published","published":"2023-10-19T21:18:01.297Z","modified":"2024-09-12T15:36:41.178Z","cvss":[{"version":"3.1","score":6.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","level":"medium","assessor":"cna"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T14:35:22.984825Z"}],"euvd":[{"id":"EUVD-2023-2813","description":"TinyMCE is an open source rich text editor. A mutation cross-site scripting (mXSS) vulnerability was discovered in TinyMCE’s core undo and redo functionality. When a carefully-crafted HTML snippet passes the XSS sanitisation layer, it is manipulated as a string by internal trimming functions before being stored in the undo stack. If the HTML snippet is restored from the undo stack, the combination of the string manipulation and reparative parsing by either the browser's native [DOMParser API](https://developer.mozilla.org/en-US/docs/Web/API/DOMParser) (TinyMCE 6) or the SaxParser API (TinyMCE 5) mutates the HTML maliciously, allowing an XSS payload to be executed. This vulnerability has been patched in TinyMCE 5.10.8 and TinyMCE 6.7.1 by ensuring HTML is trimmed using node-level manipulation instead of string manipulation. Users are advised to upgrade. There are no known workarounds for this vulnerability.","status":"published","published":"2023-10-19T21:18:01Z","modified":"2024-09-12T15:36:41Z","cvss":[{"version":"3.1","score":6.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","level":"medium"}],"updated_at":"2026-11-03T00:55:57.273476Z"}],"ghsa":[{"id":"GHSA-v65r-p3vv-jjfv","title":"TinyMCE mXSS vulnerability in undo/redo, getContent API, resetContent API, and Autosave plugin","description":"### Impact\nA [mutation cross-site scripting](https://researchgate.net/publication/266654651_mXSS_attacks_Attacking_well-secured_web-applications_by_using_innerHTML_mutations) (mXSS) vulnerability was discovered in TinyMCE’s core undo and redo functionality. When a carefully-crafted HTML snippet passes the XSS sanitisation layer, it is manipulated as a string by internal trimming functions before being stored in the undo stack. If the HTML snippet is restored from the undo stack, the combination of the string manipulation and reparative parsing by either the browser's native [DOMParser API](https://developer.mozilla.org/en-US/docs/Web/API/DOMParser) (TinyMCE 6) or the [SaxParser API](https://www.tiny.cloud/docs/api/tinymce.html/tinymce.html.saxparser/) (TinyMCE 5) mutates the HTML maliciously, allowing an XSS payload to be executed.\n​This vulnerability also impacts these related TinyMCE APIs and plugins:​\n* [`tinymce.Editor.getContent({ format: 'raw' })`](https://tiny.cloud/docs/tinymce/6/apis/tinymce.editor/#getContent)\n* [`tinymce.Editor.resetContent()`](https://tiny.cloud/docs/tinymce/6/apis/tinymce.editor/#resetContent)\n* [Autosave Plugin](https://tiny.cloud/docs/tinymce/6/autosave/)\n\n### Patches\nThis vulnerability has been patched in TinyMCE 5.10.8 and TinyMCE 6.7.1 by ensuring HTML is trimmed using node-level manipulation instead of string manipulation.\n\n### Fix\nTo avoid this vulnerability:\n* Upgrade to TinyMCE 5.10.8 or higher for TinyMCE 5.x.\n* Upgrade to TinyMCE 6.7.1 or higher for TinyMCE 6.x.\n\n### Acknowledgements\nTiny Technologies would like to thank Masato Kinugawa of [Cure53](https://cure53.de/) for discovering this vulnerability.\n\n### References\n* [TinyMCE 5.10.8 Release Notes](https://tiny.cloud/docs/release-notes/release-notes5108/)\n* [TinyMCE 6.7.1 Release Notes](https://tiny.cloud/docs/tinymce/6/6.7.1-release-notes/)\n\n### For more information\nIf you have any questions or comments about this advisory:\n* Email us at \u003cinfosec@tiny.cloud\u003e\n* Open an issue in the [TinyMCE repo](https://github.com/tinymce/tinymce/issues?q=is%3Aissue+is%3Aopen+sort%3Aupdated-desc)","status":"published","published":"2023-10-19T16:36:29Z","modified":"2023-11-15T23:24:59Z","cvss":[{"version":"3.1","score":6.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","level":"medium"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T14:37:22.040291Z"},{"id":"GHSA-5vm8-hhgr-jcjp","title":"Cross-site scripting vulnerability in TinyMCE","description":"### Impact\nA cross-site scripting (XSS) vulnerability was discovered in the URL sanitization logic of the core parser for `form` elements. The vulnerability allowed arbitrary JavaScript execution when inserting a specially crafted piece of content into the editor using the clipboard or APIs, and then submitting the form. However, as TinyMCE does not allow forms to be submitted while editing, the vulnerability could only be triggered when the content was previewed or rendered outside of the editor. This impacts all users who are using TinyMCE 5.7.0 or lower.\n\n### Patches\nThis vulnerability has been patched in TinyMCE 5.7.1 by improved URL sanitization logic.\n\n### Workarounds\nTo work around this vulnerability, either:\n- Upgrade to TinyMCE 5.7.1 or higher\n- Manually sanitize `form` URL attributes using a [TinyMCE node filter](https://www.tiny.cloud/docs/api/tinymce.html/tinymce.html.domparser/#addnodefilter).\n- Disable `form` elements in your content using the [invalid_elements](https://www.tiny.cloud/docs/configure/content-filtering/#invalid_elements) setting.\n\n#### Example: Sanitizing using a node filter\n```js\neditor.parser.addNodeFilter('form', function(nodes) {\n  nodes.forEach(function(node) {\n    if (node.attributes) {\n      node.attributes.forEach(function(attr) {\n        var name = attr.name;\n        var value = attr.value;\n        // Sanitize the attribute value here or remove it entirely\n        var sanitizedValue = ...;\n        node.attr(name, santizedValue);\n      });\n    }\n  });\n});\n```\n\n#### Example: Using invalid_elements\n```js\ninvalid_elements: 'form'\n```\n\n### Acknowledgements\nTiny Technologies would like to thank Mikhail Khramenkov at Solar Security Research Team for discovering this vulnerability.\n\n### References\nhttps://www.tiny.cloud/docs/release-notes/release-notes571/#securityfixes\n\n### For more information\nIf you have any questions or comments about this advisory:\n* Open an issue in the [TinyMCE repo](https://github.com/tinymce/tinymce/issues)\n* Email us at [infosec@tiny.cloud](mailto:infosec@tiny.cloud)","status":"published","published":"2021-05-28T19:18:53Z","modified":"2023-01-09T05:05:07Z","cwes":["CWE-79"],"updated_at":"2026-11-02T14:36:11.367194Z"}],"nvd":[{"id":"CVE-2023-45818","description":"TinyMCE is an open source rich text editor. A mutation cross-site scripting (mXSS) vulnerability was discovered in TinyMCE’s core undo and redo functionality. When a carefully-crafted HTML snippet passes the XSS sanitisation layer, it is manipulated as a string by internal trimming functions before being stored in the undo stack. If the HTML snippet is restored from the undo stack, the combination of the string manipulation and reparative parsing by either the browser's native [DOMParser API](https://developer.mozilla.org/en-US/docs/Web/API/DOMParser) (TinyMCE 6) or the SaxParser API (TinyMCE 5) mutates the HTML maliciously, allowing an XSS payload to be executed. This vulnerability has been patched in TinyMCE 5.10.8 and TinyMCE 6.7.1 by ensuring HTML is trimmed using node-level manipulation instead of string manipulation. Users are advised to upgrade. There are no known workarounds for this vulnerability.","status":"published","published":"2023-10-19T22:15:10.817Z","modified":"2026-06-17T06:29:35.17Z","cvss":[{"version":"3.1","score":6.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","level":"medium","assessor":"secondary"},{"version":"3.1","score":6.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","level":"medium","assessor":"primary"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T14:08:39.058878Z"}],"osv":[{"id":"CVE-2023-45818","title":"Cross-site Scripting vulnerability in TinyMCE undo/redo, getContent API, resetContent API, and Autosave plugin","description":"TinyMCE is an open source rich text editor. A mutation cross-site scripting (mXSS) vulnerability was discovered in TinyMCE’s core undo and redo functionality. When a carefully-crafted HTML snippet passes the XSS sanitisation layer, it is manipulated as a string by internal trimming functions before being stored in the undo stack. If the HTML snippet is restored from the undo stack, the combination of the string manipulation and reparative parsing by either the browser's native [DOMParser API](https://developer.mozilla.org/en-US/docs/Web/API/DOMParser) (TinyMCE 6) or the SaxParser API (TinyMCE 5) mutates the HTML maliciously, allowing an XSS payload to be executed. This vulnerability has been patched in TinyMCE 5.10.8 and TinyMCE 6.7.1 by ensuring HTML is trimmed using node-level manipulation instead of string manipulation. Users are advised to upgrade. There are no known workarounds for this vulnerability.","status":"published","published":"2023-10-19T21:18:01.297Z","modified":"2026-10-28T02:30:56.34101147Z","cvss":[{"version":"3.1","score":6.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","level":"medium"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T15:44:34.287121Z"},{"id":"GHSA-v65r-p3vv-jjfv","title":"TinyMCE mXSS vulnerability in undo/redo, getContent API, resetContent API, and Autosave plugin","description":"### Impact\nA [mutation cross-site scripting](https://researchgate.net/publication/266654651_mXSS_attacks_Attacking_well-secured_web-applications_by_using_innerHTML_mutations) (mXSS) vulnerability was discovered in TinyMCE’s core undo and redo functionality. When a carefully-crafted HTML snippet passes the XSS sanitisation layer, it is manipulated as a string by internal trimming functions before being stored in the undo stack. If the HTML snippet is restored from the undo stack, the combination of the string manipulation and reparative parsing by either the browser's native [DOMParser API](https://developer.mozilla.org/en-US/docs/Web/API/DOMParser) (TinyMCE 6) or the [SaxParser API](https://www.tiny.cloud/docs/api/tinymce.html/tinymce.html.saxparser/) (TinyMCE 5) mutates the HTML maliciously, allowing an XSS payload to be executed.\n​This vulnerability also impacts these related TinyMCE APIs and plugins:​\n* [`tinymce.Editor.getContent({ format: 'raw' })`](https://tiny.cloud/docs/tinymce/6/apis/tinymce.editor/#getContent)\n* [`tinymce.Editor.resetContent()`](https://tiny.cloud/docs/tinymce/6/apis/tinymce.editor/#resetContent)\n* [Autosave Plugin](https://tiny.cloud/docs/tinymce/6/autosave/)\n\n### Patches\nThis vulnerability has been patched in TinyMCE 5.10.8 and TinyMCE 6.7.1 by ensuring HTML is trimmed using node-level manipulation instead of string manipulation.\n\n### Fix\nTo avoid this vulnerability:\n* Upgrade to TinyMCE 5.10.8 or higher for TinyMCE 5.x.\n* Upgrade to TinyMCE 6.7.1 or higher for TinyMCE 6.x.\n\n### Acknowledgements\nTiny Technologies would like to thank Masato Kinugawa of [Cure53](https://cure53.de/) for discovering this vulnerability.\n\n### References\n* [TinyMCE 5.10.8 Release Notes](https://tiny.cloud/docs/release-notes/release-notes5108/)\n* [TinyMCE 6.7.1 Release Notes](https://tiny.cloud/docs/tinymce/6/6.7.1-release-notes/)\n\n### For more information\nIf you have any questions or comments about this advisory:\n* Email us at \u003cinfosec@tiny.cloud\u003e\n* Open an issue in the [TinyMCE repo](https://github.com/tinymce/tinymce/issues?q=is%3Aissue+is%3Aopen+sort%3Aupdated-desc)","status":"published","published":"2023-10-19T16:36:29Z","modified":"2026-09-10T03:49:25.360614574Z","cvss":[{"version":"3.1","score":6.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","level":"medium"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T15:46:56.981655Z"},{"id":"UBUNTU-CVE-2023-45818","description":"TinyMCE is an open source rich text editor. A mutation cross-site scripting (mXSS) vulnerability was discovered in TinyMCE’s core undo and redo functionality. When a carefully-crafted HTML snippet passes the XSS sanitisation layer, it is manipulated as a string by internal trimming functions before being stored in the undo stack. If the HTML snippet is restored from the undo stack, the combination of the string manipulation and reparative parsing by either the browser's native [DOMParser API](https://developer.mozilla.org/en-US/docs/Web/API/DOMParser) (TinyMCE 6) or the SaxParser API (TinyMCE 5) mutates the HTML maliciously, allowing an XSS payload to be executed. This vulnerability has been patched in TinyMCE 5.10.8 and TinyMCE 6.7.1 by ensuring HTML is trimmed using node-level manipulation instead of string manipulation. Users are advised to upgrade. There are no known workarounds for this vulnerability.","status":"published","published":"2023-10-19T22:15:00Z","modified":"2025-10-24T05:02:17Z","cvss":[{"version":"3.1","score":6.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","level":"medium"},{"version":"3.1","score":6.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","level":"medium"}],"updated_at":"2026-11-02T16:54:22.741943Z"},{"id":"CLSA-2026-1777423184","title":"TuxCare security update for tinymce (12 CVEs)","description":"TuxCare rebuilt tinymce to address 12 CVEs. Fixed in 4.9.11-tuxcare.1.","status":"published","published":"2026-08-04T14:52:29Z","modified":"2026-10-23T13:58:18.137089536Z","updated_at":"2026-11-02T15:43:44.384419Z"},{"id":"GHSA-5vm8-hhgr-jcjp","title":"Cross-site scripting vulnerability in TinyMCE","description":"### Impact\nA cross-site scripting (XSS) vulnerability was discovered in the URL sanitization logic of the core parser for `form` elements. The vulnerability allowed arbitrary JavaScript execution when inserting a specially crafted piece of content into the editor using the clipboard or APIs, and then submitting the form. However, as TinyMCE does not allow forms to be submitted while editing, the vulnerability could only be triggered when the content was previewed or rendered outside of the editor. This impacts all users who are using TinyMCE 5.7.0 or lower.\n\n### Patches\nThis vulnerability has been patched in TinyMCE 5.7.1 by improved URL sanitization logic.\n\n### Workarounds\nTo work around this vulnerability, either:\n- Upgrade to TinyMCE 5.7.1 or higher\n- Manually sanitize `form` URL attributes using a [TinyMCE node filter](https://www.tiny.cloud/docs/api/tinymce.html/tinymce.html.domparser/#addnodefilter).\n- Disable `form` elements in your content using the [invalid_elements](https://www.tiny.cloud/docs/configure/content-filtering/#invalid_elements) setting.\n\n#### Example: Sanitizing using a node filter\n```js\neditor.parser.addNodeFilter('form', function(nodes) {\n  nodes.forEach(function(node) {\n    if (node.attributes) {\n      node.attributes.forEach(function(attr) {\n        var name = attr.name;\n        var value = attr.value;\n        // Sanitize the attribute value here or remove it entirely\n        var sanitizedValue = ...;\n        node.attr(name, santizedValue);\n      });\n    }\n  });\n});\n```\n\n#### Example: Using invalid_elements\n```js\ninvalid_elements: 'form'\n```\n\n### Acknowledgements\nTiny Technologies would like to thank Mikhail Khramenkov at Solar Security Research Team for discovering this vulnerability.\n\n### References\nhttps://www.tiny.cloud/docs/release-notes/release-notes571/#securityfixes\n\n### For more information\nIf you have any questions or comments about this advisory:\n* Open an issue in the [TinyMCE repo](https://github.com/tinymce/tinymce/issues)\n* Email us at [infosec@tiny.cloud](mailto:infosec@tiny.cloud)","status":"published","published":"2021-05-28T19:18:53Z","modified":"2021-05-27T21:29:43Z","cwes":["CWE-79"],"updated_at":"2026-11-02T15:46:38.911014Z"}]}}