{"cve":"CVE-2023-28439","nvd":{"published":"2023-03-22T21:15:18.607","modified":"2026-06-17T05:47:44.453","status":"Modified","description":"CKEditor4 is an open source what-you-see-is-what-you-get HTML editor. A cross-site scripting vulnerability has been discovered affecting Iframe Dialog and Media Embed packages. The vulnerability may trigger a JavaScript code after fulfilling special conditions: using one of the affected packages on a web page with missing proper Content Security Policy configuration; initializing the editor on an element and using an element other than `<textarea>` as a base; and destroying the editor instance. This vulnerability might affect a small percentage of integrators that depend on dynamic editor initialization/destroy mechanism.\n\nA fix is available in CKEditor4 version 4.21.0. In some rare cases, a security fix may be considered a breaking change. Starting from version 4.21.0, the Iframe Dialog plugin applies the `sandbox` attribute by default, which restricts JavaScript code execution in the iframe element. To change this behavior, configure the `config.iframe_attributes` option. Also starting from version 4.21.0, the Media Embed plugin regenerates the entire content of the embed widget by default. To change this behavior, configure the `config.embed_keepOriginalContent` option. Those who choose to enable either of the more permissive options or who cannot upgrade to a patched version should properly configure Content Security Policy to avoid any potential security issues that may arise from embedding iframe elements on their web page.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","score":6.1},"cwes":["CWE-79"],"references":["https://ckeditor.com/cke4/addon/embed","https://ckeditor.com/cke4/addon/iframe","https://github.com/ckeditor/ckeditor4/security/advisories/GHSA-vh5c-xwqv-cv9g","https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/GWKG2VCPJNETVCDTXU4X6FQ2PO6XCNGN/","https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/L4ODGOW6PYVOXHQSMWJBOCE6DXWAI33W/"],"products":["ckeditor:ckeditor","fedoraproject:fedora"],"source":"nvd","synced_at":"2026-10-19T21:37:48.383111019+00:00"},"epss":{"cve":"CVE-2023-28439","score":0.00725,"percentile":0.54095,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}