{"id":"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.","aliases":["GHSA-944x-pm95-3jpr"],"modified":"2026-06-26T11:56:02.709018041Z","published":"2026-06-24T18:06:30.077Z","database_specific":{"cwe_ids":["CWE-434"],"cna_assigner":"GitHub_M","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53948.json"},"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"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/tryghost/ghost","events":[{"introduced":"59399d8850befd5095ae1149e31f375cac9f0514"},{"fixed":"1d36c589d39f979327106bbcfb4cece7abaea502"}],"database_specific":{"extracted_events":[{"introduced":"6.19.4"},{"fixed":"6.21.1"}],"source":"AFFECTED_FIELD"}}],"versions":["v6.21.0","v6.20.1","v6.20.0","v6.19.4"],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-53948.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N"}]}