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 ...

Description

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.

Metrics

CVSS 3.1

6.8/10

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N

EPSS Probability

7.94%

94.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Ghost	Ghost	>= 4.0.0, < 4.3.3

References

https://blog.sonarsource.com/ghost-admin-takeoverExploit, Third Party Advisory
https://forum.ghost.org/t/critical-security-update-available-for-ghost-4-x/22290Vendor Advisory
https://github.com/TryGhost/Ghost/security/advisories/GHSA-9fgx-q25h-jxrgMitigation, Third Party Advisory
https://www.npmjs.com/package/ghostProduct, Third Party Advisory
https://blog.sonarsource.com/ghost-admin-takeoverExploit, Third Party Advisory
https://forum.ghost.org/t/critical-security-update-available-for-ghost-4-x/22290Vendor Advisory
https://github.com/TryGhost/Ghost/security/advisories/GHSA-9fgx-q25h-jxrgMitigation, Third Party Advisory
https://www.npmjs.com/package/ghostProduct, Third Party Advisory

Timeline

Published: Apr 29, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

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.

How severe is CVE-2021-29484?

CVE-2021-29484 has a CVSS score of 6.8/10 (MEDIUM severity). The EPSS model estimates a 7.94% probability of exploitation in the next 30 days.

How do I fix CVE-2021-29484?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.