{
"id": "GHSA-944x-pm95-3jpr",
"aliases": [
"CVE-2026-53948"
],
"details": "### 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 [[email protected] ](mailto:[email protected] ).",
"summary": "Ghost: File Upload Content-Type Spoofing",
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "6.19.4"
},
{
"fixed": "6.21.1"
}
]
}
],
"package": {
"name": "ghost",
"ecosystem": "npm"
}
}
],
"modified": "2026-08-04T21:05:40Z",
"severity": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N"
}
],
"published": "2026-08-04T21:05:39Z",
"references": [
{
"url": "https://github.com/TryGhost/Ghost/security/advisories/GHSA-944x-pm95-3jpr",
"type": "WEB"
},
{
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-53948",
"type": "ADVISORY"
},
{
"url": "https://github.com/TryGhost/Ghost/pull/26751",
"type": "WEB"
},
{
"url": "https://github.com/TryGhost/Ghost/commit/d659e752d6636144d75b9aa94062cdbc88a16b21",
"type": "WEB"
},
{
"url": "https://github.com/TryGhost/Ghost",
"type": "PACKAGE"
},
{
"url": "https://github.com/TryGhost/Ghost/releases/tag/v6.21.1",
"type": "WEB"
}
],
"schema_version": "1.4.0",
"database_specific": {
"cwe_ids": [
"CWE-434"
],
"severity": "MODERATE",
"github_reviewed": true,
"nvd_published_at": "2026-06-24T19:17:12Z",
"github_reviewed_at": "2026-08-04T21:05:39Z"
}
}