Improper isolation or compartmentalization in Ghost - CVE-2026-103277
Published: August 14, 2026 / Updated: October 1, 2026
Vulnerability identifier: #VU142540
CSH Severity: High
CVSS v4: 8.3 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-103277
CWE-ID: CWE-653
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to execute untrusted script in a staff user's admin session.
The vulnerability exists due to improper isolation or compartmentalization in the oEmbed preview in the Ghost editor when rendering externally hosted scripts. A remote attacker can supply crafted embedded content to execute untrusted script in a staff user's admin session.
User interaction is required when a staff user views the crafted oEmbed preview.
Affected software
Ghost
How to mitigate CVE-2026-103277
Install security update from vendor's website.
Ghost - update to 6.34.0