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GHSA-jx35-x7fj-vgpr BIT-ghost-2026-53949 CVE-2026-53949

Ghost Content API filter bypass reveals private fields

Medium npm
Severity
5.3 / 10
Medium · CVSS 3.1
Exploit chance (EPSS)
0.36%
Chance of exploitation in the next 30 days. Higher than 29.57% of scored vulnerabilities.
Known exploited
No
Not in CISA's catalog
Weakness
CWE-200 Exposure of Sensitive Information to an Unauthorized Actor
CWE-693 Protection Mechanism Failure
Fix
6.21.2
Upgrade ghost to this version or later

Description

Impact

The validation applied to filters on the public API endpoints could be partially bypassed, making it possible to reveal private fields via a brute force attack. If SQLite was used as the database password hashes were fully accessible. If MySQL was used as the database the password hashes' case (uppercase / lowercase) would have been lost, which would likely have rendered a further brute force attack on the discovered hashes fruitless.

Vulnerable versions

This vulnerability is present in Ghost from v5.46.1 up to v6.21.1.

Patches

v6.21.2 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.

Workarounds

If upgrading immediately is not possible, block or filter requests to Content API endpoints where the filter query parameter contains password or email (including any compound form such as users.password, users.email, authors.password, authors.email). Reject requests at a reverse proxy / WAF layer before they reach Ghost.

Example (case-insensitive) pattern to block on the raw querystring:

filter=[^&]*(password|email)

References

Ghost thanks crnkovic for disclosing this vulnerability responsibly.

For more information

If you have any questions or comments about this advisory, email Ghost at security@ghost.org.

Affected versions

npm

PackageVulnerableFixed in
ghost
>= 5.46.1, < 6.21.2
6.21.2

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 → 6.21.2

npm
npm install ghost@6.21.2
yarn
yarn add ghost@6.21.2
pnpm
pnpm add ghost@6.21.2

Severity breakdown

CVSS 3.1 5.3

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

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
None

Weakness

CWE-200: Exposure of Sensitive Information to an Unauthorized Actor

The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.

How to prevent it
  • Architecture and Design: Compartmentalize the system to have "safe" areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area. Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.

CWE-693: Protection Mechanism Failure

The product does not use or incorrectly uses a protection mechanism that provides sufficient defense against directed attacks against the product.

References

Timeline

  1. Published
  2. Last updated by the source
  3. Latest EPSS score
AdvisorySeverityWhy 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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