---
title: "CVE-2026-53943: Ghost: Cache-poisoning XSS in Ghost frontend via x-ghost-preview header"
url: https://erroneo.us/security/cve/CVE-2026-53943/
description: "CVE-2026-53943 (ghost (npm)): Ghost is a Node.js content management system. From until 6.37.0, when Ghost is behind a shared caching layer that results in…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-06-24
date_modified: 2026-07-01
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-53943"
kev: false
cvss: 9.6
epss: 0.00446
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-53943: Ghost: Cache-poisoning XSS in Ghost frontend via x-ghost-preview header

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 0.4% , percentile 38: FIRST’s model estimates a 0.4% chance of exploitation activity in the next 30 days, higher than 38% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Needs a user to click or open something. Phishing makes that realistic, but it is not wormable.
- Only applies if your dependency tree includes ghost (npm) >= 4.0.0, <= 6.36.0, fixed in 6.37.0 . Check your lockfile, including transitive dependencies.

## What it is

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.

## Affected packages

- npm `ghost` >= 4.0.0, <= 6.36.0 → fixed: 6.37.0

## Affected products (CVE record)

- TryGhost Ghost: >= 4.0.0, < 6.37.0

## Severity

- GitHub_M CVSS 3.1: 9.6 `CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H`
- GitHub CVSS 3.1: 9.6 `CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none , automatable no , technical impact total .
- FIRST EPSS (model of 2026-10-21): 0.45% probability of exploitation activity in the next 30 days; percentile 38.

## Sources

- [GitHub Advisory GHSA-62q6-4hv4-vjrw](https://github.com/advisories/GHSA-62q6-4hv4-vjrw)
- [CVE.org record CVE-2026-53943](https://www.cve.org/CVERecord?id=CVE-2026-53943)
- [NVD entry CVE-2026-53943](https://nvd.nist.gov/vuln/detail/CVE-2026-53943)
- [github.com](https://github.com/TryGhost/Ghost/security/advisories/GHSA-62q6-4hv4-vjrw)

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Source page: https://erroneo.us/security/cve/CVE-2026-53943/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt