CVE-2026-53945: Ghost Server-side Request Forgery Vulnerability

MODERATE
Advisory Identifier: GHSA-ch52-px8q-f22j
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CVSS 4.0
CWE-367 CWE-918
Published
Advisory Summary

CVE-2026-53945 is a MODERATE (CVSS 4.0) server-side request forgery vulnerability (CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition) affecting Ghost libraries in the npm ecosystem. The issue involves server-side request forgery via dns rebinding in external request handling. Remediation is available by upgrading affected packages to version 6.21.2.

CVE-2026-53945 at a Glance

CVE Identifier CVE-2026-53945
GHSA Identifier GHSA-ch52-px8q-f22j
Severity MODERATE
CVSS v3.1 Base Score 4.0
CWE Classification CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition
Affected Product Ghost
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 4.0

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

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

How to Fix CVE-2026-53945

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-2026-53945, 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-367: Time-of-check Time-of-use (TOCTOU) Race Condition, where the product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check. 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 Ghost’s private-IP check for outbound HTTP requests could be bypassed via DNS rebinding, allowing an attacker to coerce the Ghost server into reaching hosts on internal networks through features that issue external fetches. ### Vulnerable versions This vulnerability is present in Ghost from v6.0.9 up to v6.21.0. ### Patches v6.21.1 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, operators can reduce exposure by preventing the Ghost server from reaching sensitive internal ranges at the network layer — for example, egress firewall rules that block the Ghost process from initiating connections to RFC1918 networks, loopback, link-local (including `169.254.169.254`) and any other internal service ranges. Disabling features that trigger outbound fetches (oEmbed, webmentions, recommendations) will further limit the attack surface but does not remove the underlying issue. ### References Ghost thanks Oluwaseun Esther Folorunsho, Lakshmikanthan K ([@l3tchupkt](https://github.com/l3tchupkt)), [Offgrid Security](https://www.offgridsec.com/), and Baki for disclosing this vulnerability responsibly. ### For more information If you have any questions or comments about this advisory, email us at [security@ghost.org](mailto:security@ghost.org).

CVE-2026-53945 Affected Ghost Versions

1 component(s)
Fixed Versions:
6.21.2
Product / Package Ecosystem Affected Versions Fixed Version
ghost
npm/ghost
npm
≥ 6.0.9
< 6.21.2
6.21.2

References

GitHub Advisory / Wiki ADVISORY
https://github.com/TryGhost/Ghost/security/advisories/GHSA-ch52-px8q-f22j
NVD — CVE-2026-53945 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-53945
Ghost Source Repository REPOSITORY
https://github.com/TryGhost/Ghost/pull/26754
Security Fix Commit FIX COMMIT
https://github.com/TryGhost/Ghost/commit/07d604100eb3df5c9b382fce6232928c96329448
Ghost Source Repository REPOSITORY
https://github.com/TryGhost/Ghost
Ghost Release RELEASE
https://github.com/TryGhost/Ghost/releases/tag/v6.21.1

Frequently Asked Questions

What is CVE-2026-53945?
CVE-2026-53945 is a security vulnerability in Ghost involving Server-side request forgery via DNS rebinding in external request handling under CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition.
Which Ghost versions are affected?
Affected versions include releases prior to 6.21.2 across affected packages: ghost.
What version fixes CVE-2026-53945?
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-2026-53945?
CVE-2026-53945 has a CVSS v3.1 base score of 4.0 (MODERATE) with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N.
What CWE is associated with CVE-2026-53945?
CVE-2026-53945 is classified under CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition (The product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check.).
How can I check npm dependencies for CVE-2026-53945?
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-ch52-px8q-f22j",
  "modified" : "2026-08-04T21:24:12Z",
  "published" : "2026-08-04T21:24:12Z",
  "aliases" : [ "CVE-2026-53945" ],
  "summary" : "Ghost: Server-side request forgery via DNS rebinding in external request handling",
  "details" : "### Impact\n\nGhost’s private-IP check for outbound HTTP requests could be bypassed via DNS rebinding, allowing an attacker to coerce the Ghost server into reaching hosts on internal networks through features that issue external fetches.\n\n### Vulnerable versions\n\nThis vulnerability is present in Ghost from v6.0.9 up to v6.21.0.\n\n### Patches\n\nv6.21.1 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, operators can reduce exposure by preventing the Ghost server from reaching sensitive internal ranges at the network layer — for example, egress firewall rules that block the Ghost process from initiating connections to RFC1918 networks, loopback, link-local (including `169.254.169.254`) and any other internal service ranges. Disabling features that trigger outbound fetches (oEmbed, webmentions, recommendations) will further limit the attack surface but does not remove the underlying issue.\n\n### References\n\nGhost thanks Oluwaseun Esther Folorunsho, Lakshmikanthan K ([@l3tchupkt](https://github.com/l3tchupkt)), [Offgrid Security](https://www.offgridsec.com/), and Baki for disclosing this vulnerability responsibly.\n\n### For more information\n\nIf you have any questions or comments about this advisory, email us at [security@ghost.org](mailto:security@ghost.org).",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "ghost"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "6.0.9"
      }, {
        "fixed" : "6.21.2"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "< 6.21.1"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/TryGhost/Ghost/security/advisories/GHSA-ch52-px8q-f22j"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-53945"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/TryGhost/Ghost/pull/26754"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/TryGhost/Ghost/commit/07d604100eb3df5c9b382fce6232928c96329448"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/TryGhost/Ghost"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/TryGhost/Ghost/releases/tag/v6.21.1"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-367", "CWE-918" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-08-04T21:24:12Z",
    "nvd_published_at" : "2026-06-24T19:17:12Z"
  }
}