{"id":"GHSA-wvp2-4qqp-4h3r","summary":"Ghost: Private IP filtering bypass to make server-side requests to internal services","details":"### Impact\n\nWhen 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.\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### References\n\nGhost thanks [l3tchupkt](http://github.com/l3tchupkt) 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).","aliases":["BIT-ghost-2026-53944","CVE-2026-53944"],"modified":"2026-08-04T21:30:19.858634695Z","published":"2026-08-04T21:13:16Z","database_specific":{"github_reviewed_at":"2026-08-04T21:13:16Z","nvd_published_at":"2026-06-24T19:17:11Z","cwe_ids":["CWE-184","CWE-918"],"severity":"MODERATE","github_reviewed":true},"references":[{"type":"WEB","url":"https://github.com/TryGhost/Ghost/security/advisories/GHSA-wvp2-4qqp-4h3r"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-53944"},{"type":"WEB","url":"https://github.com/TryGhost/Ghost/pull/26749"},{"type":"WEB","url":"https://github.com/TryGhost/Ghost/commit/9b7f2212970fade08ecbec543b405190471e38d4"},{"type":"PACKAGE","url":"https://github.com/TryGhost/Ghost"},{"type":"WEB","url":"https://github.com/TryGhost/Ghost/releases/tag/v6.21.1"}],"affected":[{"package":{"name":"ghost","ecosystem":"npm","purl":"pkg:npm/ghost"},"ranges":[{"type":"SEMVER","events":[{"introduced":"6.0.9"},{"fixed":"6.21.1"}]}],"database_specific":{"last_known_affected_version_range":"\u003c= 6.21.0","source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/08/GHSA-wvp2-4qqp-4h3r/GHSA-wvp2-4qqp-4h3r.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N"}]}