CVE-2020-17480: 
JavaScript vulnerability analysis and mitigation

CVE-2020-17480 affects TinyMCE versions before 4.9.7 and 5.x before 5.1.4. The vulnerability allows cross-site scripting (XSS) in the core parser, the paste plugin, and the visualchars plugin by using the clipboard or APIs to insert content into the editor (NVD, GitHub Advisory).

The vulnerability is classified as a cross-site scripting (XSS) issue with a CVSS v3.1 Base Score of 6.1 (Medium) and vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N. The vulnerability allows arbitrary JavaScript execution when inserting specially crafted content into the editor via the clipboard or APIs (NVD, GitHub Advisory).

Successful exploitation of this vulnerability could allow an attacker to execute arbitrary JavaScript code in the context of the user's browser session, potentially leading to theft of sensitive information or manipulation of editor content (GitHub Advisory).

The vulnerability can be exploited by inserting specially crafted content into the editor through either clipboard operations or API calls. The attack requires user interaction as indicated by the CVSS UI (User Interaction) metric (NVD).

The vulnerability has been patched in TinyMCE versions 4.9.7 and 5.1.4 through improved parser logic and HTML sanitization. For users unable to upgrade immediately, workarounds include disabling the impacted plugins or manually sanitizing content using the BeforeSetContent event (GitHub Advisory, Tiny Release Notes).