Ghost: Private IP filtering bypass to make server-side requests to internal services

published 2026-06-24 4 mo ago modified 2026-10-25 14 d ago also BIT-ghost-2026-53944 , EUVD-2026-39025 , GHSA-wvp2-4qqp-4h3r

cvss: 5.8; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.3%; EPSS 0.3% chance of exploitation in 30 days, percentile 26%
public exploits: 0; none known

Ghost is a Node.js content management system. From 6.0.9 until 6.21.1, when making an external request, it is possible to bypass the IP filter that ensures the request isn't going to an internal service using an IPv6 literal which maps to a private IPv4 address. This vulnerability is fixed in 6.21.1.

Patch / fix

fixed in 3 links 3

npm ghost 6.21.1
bitnami ghost 6.21.1
ghost ghost 6.21.1

github.com/TryGhost/Ghost@9b7f221 commit
github.com/TryGhost/Ghost#26749 pull request
github.com/TryGhost/Ghost/releases/tag/v6.21.1 release

CISA SSVC

Exploitation: none
Automatable: yes
Technical impact: partial
Assessed: 4 mo ago (2026-06-24)

Exploit prediction

0.33% chance of exploitation in the next 30 days, higher than 26% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	5.8	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
GitHub	3.1	5.8	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
OSV	3.1	5.8	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

Affected packages

ecosystem	package	affected	fixed in
npm	ghost	>=6.0.9, <6.21.1	6.21.1
bitnami	ghost	>=6.0.9, <6.21.1	6.21.1

Affected products

TryGhost Ghost

Classification

Weakness

CWE-184 Incomplete List of Disallowed Inputs
CWE-918 Server-Side Request Forgery

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.

Summary