DOM XSS in Theme Preview
CVE-2021-29484

6.8MEDIUM

Key Information:

Vendor

Tryghost

Status
Ghost
Vendor
CVE Published:
29 April 2021

What is CVE-2021-29484?

Ghost is a Node.js CMS. An unused endpoint added during the development of 4.0.0 has left sites vulnerable to untrusted users gaining access to Ghost Admin. Attackers can gain access by getting logged in users to click a link containing malicious code. Users do not need to enter credentials and may not know they've visited a malicious site. Ghost(Pro) has already been patched. We can find no evidence that the issue was exploited on Ghost(Pro) prior to the patch being added. Self-hosters are impacted if running Ghost a version between 4.0.0 and 4.3.2. Immediate action should be taken to secure your site. The issue has been fixed in 4.3.3, all 4.x sites should upgrade as soon as possible. As the endpoint is unused, the patch simply removes it. As a workaround blocking access to /ghost/preview can also mitigate the issue.

Affected Version(s)

Ghost >= 4.0.0, < 4.3.3

References

https://github.com/TryGhost/Ghost/security/advisories/GHS...
x_refsource_CONFIRM
https://forum.ghost.org/t/critical-security-update-availa...
x_refsource_MISC
https://www.npmjs.com/package/ghost
x_refsource_MISC

EPSS Score

82% chance of being exploited in the next 30 days.

CVSS V3.1

Score:
6.8
Severity:
MEDIUM
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
High
Privileges Required:
None
User Interaction:
Required
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

JSON
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CVE-2021-29484 : DOM XSS in Theme Preview