CVE-2026-53943 (CVSS 9.6)

Description

Ghost is a Node.js content management system. From until 6.37.0, when Ghost is behind a shared caching layer that results in cached content being shared between different visitors, an unauthenticated user could send an x-ghost-preview header that altered the rendered frontend response. In affected cache configurations, that response could be stored and served to subsequent visitors requesting the same page, allowing cache poisoning of request-specific preview output. When running Ghost's frontend and admin panel on the same domain this could be used to take over staff user accounts. When running these on different domains staff accounts have no exposure. This vulnerability is fixed in 6.37.0.

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CVSS v3.1 Score

9.6

CRITICAL

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

EPSS — Exploit Prediction

0.0024

Probability of exploitation

0.16%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-524 CWE-524

References

Other References

https://github.com/TryGhost/Ghost/security/advisories/GHSA-62q6-4hv4-vjrw

Frequently Asked Questions

What is CVE-2026-53943? +

Ghost is a Node.js content management system. From until 6.37.0, when Ghost is behind a shared caching layer that results in cached content being shared between different visitors, an unauthenticated user could send an x-ghost-preview header that altered the rendered frontend response. In affected cache configurations, that response could be stored and served to subsequent visitors requesting the same page, allowing cache poisoning of request-specific preview output. When running Ghost's frontend and admin panel on the same domain this could be used to take over staff user accounts. When running these on different domains staff accounts have no exposure. This vulnerability is fixed in 6.37.0. It has a CVSS v3.1 base score of 9.6 (CRITICAL).

How severe is CVE-2026-53943? +

CVE-2026-53943 has a CVSS v3.1 score of 9.6 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0024, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-53943? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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