Ghost: Stored XSS via SVG Uploads Bypassing Sanitization

### Impact SVG media thumbnails, and SVG images uploaded with a non-SVG file extension, were stored without sanitization. This allowed any staff user, including Contributors, to host scripts on the site's domain, possibly resulting in compromise of other staff users' admin sessions. ### Vulnerable versions This vulnerability is present in Ghost from v4.22.0 up to v6.64.0. ### Patches v6.65.0 contains a fix for this issue. ### How to update For 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). If your Ghost is a Ghost-CLI install see our documentation on [updating it to the latest version here](https://docs.ghost.org/update). ### References Ghost thanks [Ibrahim AlJaafreh](https://cystack.ps) of Cystack Red Team, [Anand Prajapati](https://www.linkedin.com/in/anand-prajapati-7a265a369/), [白墨](https://github.com/5255fgh), and [Nhat Anh Vu](https://github.com/nhattanhh) for disclosing this vulnerability responsibly. ### For more information If you have any questions or comments about this advisory, email us at [security@ghost.org](mailto:security@ghost.org). Source Code Location: https://github.com/TryGhost/Ghost Affected Packages: - npm:ghost, affected >= 4.22.0, < 6.65.0, patched in 6.65.0 CWEs: - CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') - CWE-434: Unrestricted Upload of File with Dangerous Type CVSS: - Primary: score 7.3, CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N - CVSS_V3: score 7.3, CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N References: - https://github.com/TryGhost/Ghost/security/advisories/GHSA-8575-cr6v-7jh4 - https://nvd.nist.gov/vuln/detail/CVE-2026-105649 - https://github.com/TryGhost/Ghost/issues/30919 - https://github.com/TryGhost/Ghost/commit/80686226d23df56749f6b7ebb484850a8eba8072 - https://github.com/TryGhost/Ghost/releases/tag/v6.65.0 - https://github.com/advisories/GHSA-8575-cr6v-7jh4