CVE-2026-53949: Ghost Ghost Content API Filter Bypass Vulnerability

MODERATE
Advisory Identifier: GHSA-jx35-x7fj-vgpr
Share
CVSS 5.3
CWE-693 CWE-200
Published
Advisory Summary

CVE-2026-53949 is a MODERATE (CVSS 5.3) ghost content api filter bypass vulnerability (CWE-693: Protection Mechanism Failure) affecting Ghost libraries in the npm ecosystem. The issue involves ghost content api filter bypass reveals private fields. Remediation is available by upgrading affected packages to version 6.21.2.

CVE-2026-53949 at a Glance

CVE Identifier CVE-2026-53949
GHSA Identifier GHSA-jx35-x7fj-vgpr
Severity MODERATE
CVSS v3.1 Base Score 5.3
CWE Classification CWE-693: Protection Mechanism Failure
Affected Product Ghost
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 5.3

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality Low (C:L)
Integrity None (I:N)
Availability None (A:N)

How to Fix CVE-2026-53949

To remediate this vulnerability, upgrade all affected Ghost dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

ghost fixed: 6.21.2 
npm install ghost@6.21.2
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

npm ls ghost

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2026-53949, inspect your project dependencies using npm:

npm ls ghost

Analyze the terminal output to locate any version of Ghost in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 6.21.2), your application is affected.

Note: The npm ls ghost command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-693: Protection Mechanism Failure, where the product does not use or incorrectly uses a protection mechanism that provides sufficient defense against directed attacks against the product. In Ghost, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### 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](https://hub.docker.com/_/ghost). Updating a Docker-based Ghost instance [is documented here](https://docs.ghost.org/install/docker#updating-ghost). If your Ghost is a Ghost-CLI install see our documentation on [updating it to the latest version here](https://docs.ghost.org/update). ### 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](mailto:security@ghost.org).

CVE-2026-53949 Affected Ghost Versions

1 component(s)
Fixed Versions:
6.21.2
Product / Package Ecosystem Affected Versions Fixed Version
ghost
npm/ghost
npm
≥ 5.46.1
< 6.21.2
6.21.2

References

Ghost Source Repository REPOSITORY
https://github.com/TryGhost/Ghost
GitHub Advisory / Wiki ADVISORY
https://github.com/TryGhost/Ghost/security/advisories/GHSA-jx35-x7fj-vgpr
NVD — CVE-2026-53949 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-53949
Ghost Release RELEASE
https://github.com/TryGhost/Ghost/releases/tag/v6.21.2

Frequently Asked Questions

What is CVE-2026-53949?
CVE-2026-53949 is a security vulnerability in Ghost involving Ghost Content API filter bypass reveals private fields under CWE-693: Protection Mechanism Failure.
Which Ghost versions are affected?
Affected versions include releases prior to 6.21.2 across affected packages: ghost.
What version fixes CVE-2026-53949?
Upgrading to 6.21.2 (or the latest patched release for your respective branch) resolves the vulnerability.
Is ghost affected?
Yes, ghost is affected in releases prior to 6.21.2. Upgrade your dependency to 6.21.2 or later.
What is the CVSS score of CVE-2026-53949?
CVE-2026-53949 has a CVSS v3.1 base score of 5.3 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N.
What CWE is associated with CVE-2026-53949?
CVE-2026-53949 is classified under 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.).
How can I check npm dependencies for CVE-2026-53949?
Run the dependency tree command: 'npm ls ghost'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-jx35-x7fj-vgpr",
  "modified" : "2026-08-05T14:42:47Z",
  "published" : "2026-08-05T14:42:47Z",
  "aliases" : [ "CVE-2026-53949" ],
  "summary" : "Ghost Content API filter bypass reveals private fields",
  "details" : "### Impact\n\nThe 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.\n\n### Vulnerable versions\n\nThis vulnerability is present in Ghost from v5.46.1 up to v6.21.1.\n\n### Patches\n\nv6.21.2 contains a fix for this issue.\n\n### How to update\n\nFor self-hosters using Docker, find [Docker's official Ghost image here](https://hub.docker.com/_/ghost). Updating a Docker-based Ghost instance [is documented here](https://docs.ghost.org/install/docker#updating-ghost). \n\nIf your Ghost is a Ghost-CLI install see our documentation on [updating it to the latest version here](https://docs.ghost.org/update). \n\n### Workarounds\n\nIf 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.\n\nExample (case-insensitive) pattern to block on the raw querystring:\n\n```\nfilter=[^&]*(password|email)\n```\n\n### References\n\nGhost thanks crnkovic for disclosing this vulnerability responsibly.\n\n### For more information\n\nIf you have any questions or comments about this advisory, email Ghost at [security@ghost.org](mailto:security@ghost.org).",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "ghost"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "5.46.1"
      }, {
        "fixed" : "6.21.2"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/TryGhost/Ghost/security/advisories/GHSA-jx35-x7fj-vgpr"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-53949"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/TryGhost/Ghost"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/TryGhost/Ghost/releases/tag/v6.21.2"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-200", "CWE-693" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-08-05T14:42:47Z",
    "nvd_published_at" : "2026-06-24T19:17:12Z"
  }
}