{"id":"CVE-2026-53948","aliases":["BIT-ghost-2026-53948","GHSA-944x-pm95-3jpr"],"url":"https://o3.security/vulnerability/CVE-2026-53948","summary":"Ghost: File Upload Content-Type Spoofing","details":"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":"2026-06-24T18:06:30.077Z","modified":"2026-08-12T03:51:08.248904205Z","cvss":{"score":5.4,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"ghost","fixedVersion":"6.21.1"}],"fix":null,"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53948.json"},{"type":"ADVISORY","url":"https://github.com/TryGhost/Ghost/security/advisories/GHSA-944x-pm95-3jpr"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-53948"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:08.248904205Z"}}