Ghost CMS EUVD-2026-92621

Requires an authenticated Ghost staff account of any role, including the lowest-privilege Contributor, on Ghost versions 6.56.0 through 6.66.x (fixed in 6.67.0). The attacker must be able to create a bookmark card pointing to a website they control that serves a crafted SVG, which is then processed by Ghost's bundled image-processing library. Limiting factors: there is no anonymous/unauthenticated path despite the vendor's PR:N vector - a valid staff login (or a compromised/invited Contributor) is mandatory, and instances already upgraded to 6.67.0 are not affected.

This is a credible, high-priority RCE in Ghost CMS (CWE-94 code injection) achievable by any staff user down to the low-privilege Contributor role, yielding full C:H/I:H/A:H impact on the server. The vendor CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:R, 8.8) conflicts with the description: it encodes PR:N (unauthenticated), yet the text explicitly requires an authenticated staff/Contributor account, so the real-world privilege requirement is PR:L, not PR:N - treat the 'unauthenticated' implication of the vendor vector as inaccurate and verify with the GHSA advisory. No EPSS score, KEV listing, or POC was provided, so there is no public exploit identified at time of analysis and no evidence of active exploitation. Net: a genuinely serious post-authentication RCE that insider or compromised-Contributor accounts can weaponize, but the authentication barrier and absence of KEV/POC signals place it below internet-wide, unauthenticated mass-exploitation threats; the main unknown is real-world exploitation probability since EPSS is missing.

An attacker who holds or phishes a low-privilege Ghost Contributor account creates a bookmark card pointing at a website they control, which serves a malicious SVG. When Ghost's bundled image-processing library handles that SVG, attacker-supplied content is executed as code, giving arbitrary command execution on the Ghost server. No public proof-of-concept was provided, so exploitation would require independent development against the vulnerable SVG-handling path in versions 6.56.0 through 6.66.x.