GHSA-ch52-px8q-f22j BIT-ghost-2026-53945 CVE-2026-53945
Ghost: Server-side request forgery via DNS rebinding in external request handling
- Severity
- 4.0 / 10
- Medium · CVSS 3.1
- Exploit chance (EPSS)
- 0.21%
- Chance of exploitation in the next 30 days. Higher than 11.77% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-367 Time-of-check Time-of-use (TOCTOU) Race Condition
- CWE-918 Server-Side Request Forgery (SSRF)
- Fix
6.21.2- Upgrade ghost to this version or later
Description
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. 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, 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), Offgrid Security, 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.
Affected versions
npm
| Package | Vulnerable | Fixed in |
|---|---|---|
| ghost | >= 6.0.9, < 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 4.0
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N
- Attack vector
- Network
- Attack complexity
- High
- Privileges required
- None
- User interaction
- None
- Scope
- Changed
- Confidentiality
- None
- Integrity
- Low
- Availability
- None
Weakness
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 to prevent it
- Implementation: The most basic advice for TOCTOU vulnerabilities is to not perform a check before the use. This does not resolve the underlying issue of the execution of a function on a resource whose state and identity cannot be assured, but it does help to limit the false sense of security given by the check.
- Implementation: When the file being altered is owned by the current user and group, set the effective gid and uid to that of the current user and group when executing this statement.
- Architecture and Design: Limit the interleaving of operations on files from multiple processes.
- Implementation, Architecture and Design: If you cannot perform operations atomically and you must share access to the resource between multiple processes or threads, then try to limit the amount of time (CPU cycles) between the check and use of the resource. This will not fix the problem, but it could make it more difficult for an attack to succeed.
- Implementation: Recheck the resource after the use call to verify that the action was taken appropriately.
- Architecture and Design: Ensure that some environmental locking mechanism can be used to protect resources effectively.
- Implementation: Ensure that locking occurs before the check, as opposed to afterwards, such that the resource, as checked, is the same as it is when in use.
CWE-918: Server-Side Request Forgery (SSRF)
The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.
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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