{"cve":{"cve_id":"CVE-2023-28439","is_kev":false,"kev_date_added":null,"kev_vendor_project":null,"kev_product":null,"kev_vulnerability_name":null,"kev_short_description":null,"kev_required_action":null,"kev_due_date":null,"kev_known_ransomware":null,"kev_notes":null,"kev_cwes":null,"epss_score":0.00725,"epss_percentile":0.51405,"epss_as_of":"2026-08-26","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.","published_at":"2023-03-22T20:55:00.208000Z","last_modified_at":null,"cvss_v3_score":4.7,"cvss_v3_vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N","cvss_v3_severity":"MEDIUM","cvss_v4_score":null,"cvss_v4_vector":null,"cvss_v4_severity":null,"ssvc_decision":null,"ssvc_exploitation":"none","ssvc_automatable":false,"ssvc_technical_impact":"partial","cwes":["CWE-79"],"nvd_references":["https://github.com/ckeditor/ckeditor4/security/advisories/GHSA-vh5c-xwqv-cv9g","https://ckeditor.com/cke4/addon/embed","https://ckeditor.com/cke4/addon/iframe","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/VCYKD3JZWWA3ESOZG4PHJJEXT4EYIUIQ/","https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/L4ODGOW6PYVOXHQSMWJBOCE6DXWAI33W/"],"vuln_status":null,"trending_score":null,"is_trending":false,"has_trended":false,"trended_number_one":false,"trending_peak_score":null,"trending_peak_rank":null,"started_trending_at":null,"trended_number_one_at":null,"summary_generated":null,"summary_generated_at":null,"summary_model":null,"created_at":"2026-06-24T00:09:39.878444Z","updated_at":"2026-06-29T01:28:55.728164Z"},"effective_severity":"MEDIUM","badges":[],"impact_analysis":[],"cvss_v3_decoded":{"version":"3.1","metrics":[{"metric":"AV","name":"Attack Vector","value":"N","value_label":"Network"},{"metric":"AC","name":"Attack Complexity","value":"H","value_label":"High"},{"metric":"PR","name":"Privileges Required","value":"N","value_label":"None"},{"metric":"UI","name":"User Interaction","value":"R","value_label":"Required"},{"metric":"S","name":"Scope","value":"C","value_label":"Changed"},{"metric":"C","name":"Confidentiality","value":"L","value_label":"Low"},{"metric":"I","name":"Integrity","value":"L","value_label":"Low"},{"metric":"A","name":"Availability","value":"N","value_label":"None"}]},"cvss_v4_decoded":{"version":null,"metrics":[]},"affected":[{"vendor_slug":"ckeditor","vendor_name":"ckeditor","product_slug":"ckeditor4","product_name":"ckeditor4","version_start":"< 4.21.0","version_start_inclusive":true,"version_end":"< 4.21.0","version_end_inclusive":true,"cpe23_uri":"cve5:ckeditor:ckeditor4:< 4.21.0:< 4.21.0"}],"exploit_refs":[],"news":[],"references":[{"url":"https://github.com/ckeditor/ckeditor4/security/advisories/GHSA-vh5c-xwqv-cv9g","source_type":"VENDOR_ADVISORY","tags":["advisory"]},{"url":"https://ckeditor.com/cke4/addon/embed","source_type":"MISC","tags":[]},{"url":"https://ckeditor.com/cke4/addon/iframe","source_type":"MISC","tags":[]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/GWKG2VCPJNETVCDTXU4X6FQ2PO6XCNGN/","source_type":"MAILING_LIST","tags":["mailing-list"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/VCYKD3JZWWA3ESOZG4PHJJEXT4EYIUIQ/","source_type":"MAILING_LIST","tags":["mailing-list"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/L4ODGOW6PYVOXHQSMWJBOCE6DXWAI33W/","source_type":"MAILING_LIST","tags":["mailing-list"]}],"timeline":[{"type":"published","at":"2023-03-22T20:55:00.208000Z","label":"CVE published","source":null},{"type":"cvss_changed","at":"2026-06-28T17:27:31.932191Z","label":"CVSS score revised","source":"cvelistv5"},{"type":"cvss_changed","at":"2026-06-28T17:27:31.932191Z","label":"CVSS score revised","source":"cvelistv5"},{"type":"cvss_changed","at":"2026-06-28T17:27:31.932191Z","label":"CVSS score revised","source":"cvelistv5"},{"type":"ssvc_changed","at":"2026-06-29T01:28:55.728164Z","label":"SSVC decision revised","source":"vulnrichment"},{"type":"ssvc_changed","at":"2026-06-29T01:28:55.728164Z","label":"SSVC decision revised","source":"vulnrichment"},{"type":"ssvc_changed","at":"2026-06-29T01:28:55.728164Z","label":"SSVC decision revised","source":"vulnrichment"}]}