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.
Remediation
References
https://github.com/tinymce/tinymce/security/advisories/GHSA-v65r-p3vv-jjfv
https://researchgate.net/publication/266654651_mXSS_attacks_Attacking_well-secured_web-applications_by_using_innerHTML_mutations
https://tiny.cloud/docs/release-notes/release-notes5108/#securityfixes
https://tiny.cloud/docs/tinymce/6/6.7.1-release-notes/#security-fixes
https://www.tiny.cloud/docs/api/tinymce.html/tinymce.html.saxparser/
Related Vulnerabilities
CVE-2021-26073 Vulnerability in npm package atlassian-connect-express
CVE-2020-9492 Vulnerability in maven package org.apache.hadoop:hadoop-hdfs-client
CVE-2021-20195 Vulnerability in maven package org.keycloak:keycloak-core
CVE-2022-24697 Vulnerability in maven package org.apache.kylin:kylin-spark-engine
CVE-2021-45029 Vulnerability in maven package org.apache.shenyu:shenyu-common