GHSA-62q6-4hv4-vjrw BIT-ghost-2026-53943 CVE-2026-53943
Ghost: Cache-poisoning XSS in Ghost frontend via x-ghost-preview header
- Severity
- 9.6 / 10
- Critical · CVSS 3.1
- Exploit chance (EPSS)
- 0.45%
- Chance of exploitation in the next 30 days. Higher than 38.84% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-524 Use of Cache Containing Sensitive Information
- Fix
6.37.0- Upgrade ghost to this version or later
Description
Impact
When Ghost is behind a shared caching layer that results in cached content being shared between different visitors (e.g., Fastly, Cloudflare, nginx proxy_cache, and others), 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.
Vulnerable versions
This vulnerability is present in Ghost from v4.0 up to v6.36.0.
Patches
v6.37.0 contains a fix for this issue.
How to update
For self-hosters using Docker, find Docker's official Ghost image here. Updating a Docker-based Ghost instance is documented here.
If your Ghost is a Ghost-CLI install see our documentation on updating it to the latest version here.
If you suspect a credential compromise, use the “Reset all authentication” dialogue under Settings / Danger Zone. This is available starting with Ghost v6.41.0.
Workarounds
At the caching layer, bypass the cache for x-ghost-preview requests.
References
Ghost thanks CryptoCat for disclosing this vulnerability responsibly.
For more information
If you have any questions or comments about this advisory, email us at security@ghost.org.
Affected versions
npm
| Package | Vulnerable | Fixed in |
|---|---|---|
| ghost | >= 4.0.0, < 6.37.0 |
6.37.0 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
ghost npm → 6.37.0
- npm
npm install ghost@6.37.0- yarn
yarn add ghost@6.37.0- pnpm
pnpm add ghost@6.37.0
Severity breakdown
CVSS 3.1 9.6
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Weakness
CWE-524: Use of Cache Containing Sensitive Information
The code uses a cache that contains sensitive information, but the cache can be read by an actor outside of the intended control sphere.
How to prevent it
- Architecture and Design: Protect information stored in cache.
- Architecture and Design: Do not store unnecessarily sensitive information in the cache.
- Architecture and Design: Consider using encryption in the cache.
References
Advisories
Packages
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-x3mg-q38v-m562 Ghost: Authorization Issue Allowed Author Role to Delete any Post | Medium | Also affects ghost |
| GHSA-8575-cr6v-7jh4 Ghost: Stored XSS via SVG Uploads Bypassing Sanitization | High | Also affects ghost |
| GHSA-r7f2-6fj8-6fg2 Ghost: Private IP Filtering Bypass via IPv6 Transition Addresses | Medium | Also affects ghost |
| GHSA-322m-ff4g-9vx9 Ghost: Server-Side Request Forgery in Bookmark Fetching | Medium | Also affects ghost |
| GHSA-fwh9-qg68-vxp4 Ghost: Regular Expression Denial of Service in Content Import | Medium | Also affects ghost |
| GHSA-9m4w-fmjw-fvjq Ghost: Regular Expression Denial of Service in External Media Inliner | Medium | Also affects ghost |
| GHSA-hqq2-xqr2-fmx2 Ghost : Stored XSS via SVG Files in Content Imports | Medium | Also affects ghost |
| GHSA-69qc-f5m6-889c Ghost: Stored XSS via Embed Card Previews | High | Also affects ghost |
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