{"cve":{"cve_id":"CVE-2026-53948","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":null,"epss_percentile":null,"epss_as_of":null,"description":"Ghost is a Node.js content management system. From 6.19.4 until 6.21.1, insufficient validation of the client-supplied Content-Type on Ghost's Admin API file upload endpoint allowed uploaded files to be served from the site with an attacker-chosen content type on S3/GCS storage backends. On installations that serve uploaded files from the same origin as the site, this could have been used to facilitate stored cross-site scripting against site visitors or staff. This vulnerability is fixed in 6.21.1.","published_at":"2026-06-24T18:06:30.077000Z","last_modified_at":null,"cvss_v3_score":5.4,"cvss_v3_vector":"CVSS:3.1/AV:N/AC:L/PR:L/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":null,"ssvc_automatable":null,"ssvc_technical_impact":null,"cwes":["CWE-434"],"nvd_references":["https://github.com/TryGhost/Ghost/security/advisories/GHSA-944x-pm95-3jpr"],"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":"2026-06-28T17:55:28.590503Z","updated_at":"2026-06-28T23:30:53.764986Z"},"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":"L","value_label":"Low"},{"metric":"PR","name":"Privileges Required","value":"L","value_label":"Low"},{"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":"tryghost","vendor_name":"TryGhost","product_slug":"ghost","product_name":"Ghost","version_start":">= 6.19.4, < 6.21.1","version_start_inclusive":true,"version_end":">= 6.19.4, < 6.21.1","version_end_inclusive":true,"cpe23_uri":"cve5:tryghost:ghost:>= 6.19.4, < 6.21.1:>= 6.19.4, < 6.21.1"}],"exploit_refs":[],"news":[],"references":[{"url":"https://github.com/TryGhost/Ghost/security/advisories/GHSA-944x-pm95-3jpr","source_type":"VENDOR_ADVISORY","tags":["advisory"]}],"timeline":[{"type":"published","at":"2026-06-24T18:06:30.077000Z","label":"CVE published","source":null}]}