{"id":"CVE-2026-53948","aliases":["BIT-ghost-2026-53948","EUVD-2026-39021","GHSA-944x-pm95-3jpr"],"status":"published","title":"Ghost: File Upload Content-Type Spoofing","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.","severity":{"version":"3.1","score":5.4,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-12","score":0.00226,"percentile":0.13417,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-434"],"published":"2026-06-24T18:06:30Z","modified":"2026-10-28T02:31:03Z","fixes":[{"ecosystem":"npm","package":"ghost","fixed_in":["6.21.1"],"sources":["ghsa","osv"]},{"ecosystem":"Bitnami","package":"ghost","fixed_in":["6.21.1"],"sources":["osv"]}],"affected":[{"source":"ghsa","ecosystem":"npm","package":"ghost","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.19.4"},{"fixed":"6.21.1"}]}]},{"source":"osv","ecosystem":"Bitnami","package":"ghost","ranges":[{"type":"SEMVER","events":[{"introduced":"6.19.4"},{"fixed":"6.21.1"}]}]},{"source":"osv","ecosystem":"npm","package":"ghost","ranges":[{"type":"SEMVER","events":[{"introduced":"6.19.4"},{"fixed":"6.21.1"}]}]}],"products":[{"vendor":"tryghost","product":"ghost"}],"references":[{"url":"https://github.com/TryGhost/Ghost/security/advisories/GHSA-944x-pm95-3jpr","tags":["x_refsource_CONFIRM","web","advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-53948","tags":["web","advisory"]},{"url":"https://github.com/TryGhost/Ghost/pull/26751","tags":["web"]},{"url":"https://github.com/TryGhost/Ghost/commit/d659e752d6636144d75b9aa94062cdbc88a16b21","tags":["web"]},{"url":"https://github.com/TryGhost/Ghost/releases/tag/v6.21.1","tags":["web"]},{"url":"https://github.com/advisories/GHSA-944x-pm95-3jpr"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53948.json","tags":["advisory"]},{"url":"https://github.com/TryGhost/Ghost","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-53948","title":"Ghost: File Upload Content-Type Spoofing","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.","status":"published","published":"2026-06-24T18:06:30.077Z","modified":"2026-06-25T13:17:23.333Z","cvss":[{"version":"3.1","score":5.4,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N","level":"medium","assessor":"cna"}],"cwes":["CWE-434"],"updated_at":"2026-11-02T14:20:00.11477Z"}],"euvd":[{"id":"EUVD-2026-39021","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.","status":"published","published":"2026-06-24T18:06:30Z","modified":"2026-06-25T13:17:23Z","cvss":[{"version":"3.1","score":5.4,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N","level":"medium"}],"updated_at":"2026-11-02T18:20:29.213001Z"}],"ghsa":[{"id":"GHSA-944x-pm95-3jpr","title":"Ghost: File Upload Content-Type Spoofing","description":"### Impact\n\nInsufficient 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.\n\n### Vulnerable versions\n\nThis vulnerability is present in Ghost from v6.19.4 up to v6.21.0.\n\n### Patches\n\nv6.21.1 contains a fix for this issue.\n\n### How to update\n\nFor self-hosters using Docker, find [Docker's official Ghost image here](https://hub.docker.com/_/ghost). Updating a Docker-based Ghost instance [is documented here](https://docs.ghost.org/install/docker#updating-ghost). \n\nIf your Ghost is a Ghost-CLI install see our documentation on [updating it to the latest version here](https://docs.ghost.org/update). \n\n### For more information\n\nIf you have any questions or comments about this advisory, email us at [security@ghost.org](mailto:security@ghost.org).","status":"published","published":"2026-08-04T21:05:39Z","modified":"2026-08-04T21:05:41Z","cvss":[{"version":"3.1","score":5.4,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N","level":"medium"}],"cwes":["CWE-434"],"updated_at":"2026-11-02T14:40:56.852119Z"}],"nvd":[{"id":"CVE-2026-53948","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.","status":"published","published":"2026-06-24T19:17:12.46Z","modified":"2026-10-25T22:10:00.15Z","cvss":[{"version":"3.1","score":5.4,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N","level":"medium","assessor":"secondary"}],"cwes":["CWE-434"],"updated_at":"2026-11-02T14:12:25.67873Z"}],"osv":[{"id":"CVE-2026-53948","title":"Ghost: File Upload Content-Type Spoofing","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.","status":"published","published":"2026-06-24T18:06:30.077Z","modified":"2026-10-28T02:31:03.331549542Z","cvss":[{"version":"3.1","score":5.4,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N","level":"medium"}],"cwes":["CWE-434"],"updated_at":"2026-11-02T15:45:08.132336Z"},{"id":"GHSA-944x-pm95-3jpr","title":"Ghost: File Upload Content-Type Spoofing","description":"### Impact\n\nInsufficient 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.\n\n### Vulnerable versions\n\nThis vulnerability is present in Ghost from v6.19.4 up to v6.21.0.\n\n### Patches\n\nv6.21.1 contains a fix for this issue.\n\n### How to update\n\nFor self-hosters using Docker, find [Docker's official Ghost image here](https://hub.docker.com/_/ghost). Updating a Docker-based Ghost instance [is documented here](https://docs.ghost.org/install/docker#updating-ghost). \n\nIf your Ghost is a Ghost-CLI install see our documentation on [updating it to the latest version here](https://docs.ghost.org/update). \n\n### For more information\n\nIf you have any questions or comments about this advisory, email us at [security@ghost.org](mailto:security@ghost.org).","status":"published","published":"2026-08-04T21:05:39Z","modified":"2026-08-04T21:15:19.787379123Z","cvss":[{"version":"3.1","score":5.4,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N","level":"medium"}],"cwes":["CWE-434"],"updated_at":"2026-11-02T15:46:43.123867Z"},{"id":"BIT-ghost-2026-53948","title":"Ghost: File Upload Content-Type Spoofing","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.","status":"published","published":"2026-06-30T23:39:24.628Z","modified":"2026-07-08T08:11:31.452236613Z","updated_at":"2026-11-02T15:28:29.999658Z"}]}}