CVE-2026-70590: Blind Password Hash Disclosure in TryGhost Ghost Admin API via Insecure Filter Mapping
Vulnerability ID: CVE-2026-70590
CVSS Score: 4.8
Published: 2026-08-04
An authenticated staff-level user can perform a side-channel, boolean-based blind database query attack through the Ghost Admin API to systematically extract the hashed passwords (bcrypt) of other staff users, including administrators, due to insecure filter mapping.
TL;DR
Authenticated staff-level users can exploit insecure nested filter mapping in the Ghost Admin API to extract bcrypt password hashes of other users, including administrators, via boolean-based blind SQL side-channel queries.
Technical Details
- CWE ID: CWE-200
- Attack Vector: Network (AV:N/AC:H/PR:H/UI:R/S:U/C:L/I:H/A:N)
- CVSS Score: 4.8
- EPSS Score: 0.0
- Impact: Information Disclosure (Password Hashes)
- Exploit Status: None (No public weaponized exploit)
- KEV Status: Not Listed
Affected Systems
- Ghost (TryGhost/Ghost) CMS
-
Ghost: < 6.54.1 (Fixed in:
6.54.1)
Code Analysis
Commit: 63c31fa
Applied NQL transformer functions to more APIs. (#29628)
@@ -2,6 +2,7 @@ const models = require('../../models');
const tpl = require('@tryghost/tpl');
const errors = require('@tryghost/errors');
const getPostServiceInstance = require('../../services/posts/posts-service-instance');
+const {rejectAdminApiRestrictedFieldsTransformer} = require('./utils/api-filter-utils');
Mitigation Strategies
- Immediate upgrade to Ghost version 6.54.1 or newer.
- Implement WAF rules to drop or block URI query parameters containing password-related strings on administrative endpoints.
Remediation Steps:
- Identify all deployed self-hosted Ghost instances.
- Execute the 'ghost update' command via Ghost-CLI to upgrade instances to version 6.54.1 or above.
- Deploy temporary WAF filters to inspect and block malicious Admin API query strings targeting critical backend properties.
- Review Ghost access logs for unexpected iterative queries containing relational parameters.
References
- GitHub Security Advisory GHSA-jm22-3w23-5q7w
- Fix Commit
- Pull Request #29628
- Release Tag v6.54.1
- CVE Registry Record
Read the full report for CVE-2026-70590 on our website for more details including interactive diagrams and full exploit analysis.
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