CVE-2026-53947: CWE-204: Observable Response Discrepancy in TryGhost Ghost
Ghost, a Node.js content management system, has a vulnerability in its members signin endpoints from versions 5.18.0 up to but not including 6.21.1. This flaw allows an unauthenticated attacker to determine if an email address is registered on a Ghost site by observing differences in response behavior. The issue is classified as CWE-204 (Observable Response Discrepancy) and has a medium severity rating with a CVSS score of 5.3. The vulnerability is fixed starting in version 6.21.1.
AI Analysis
Technical Summary
CVE-2026-53947 describes an information disclosure vulnerability in Ghost CMS versions 5.18.0 through 6.21.0. The members signin endpoints respond differently depending on whether an email address is registered, enabling unauthenticated attackers to enumerate valid member emails. This is a classic observable response discrepancy issue (CWE-204). The vulnerability does not impact confidentiality beyond email enumeration, nor does it affect integrity or availability. The fix was introduced in version 6.21.1.
Potential Impact
An attacker can confirm the existence of specific email addresses registered as members on a Ghost site without authentication. This information disclosure can facilitate targeted phishing or social engineering attacks. There is no direct impact on data integrity or system availability.
Mitigation Recommendations
Upgrade Ghost to version 6.21.1 or later, where this vulnerability is fixed. Since no official patch or temporary workaround is detailed, applying the official fix is the recommended remediation. Patch status is confirmed by the vendor stating the fix is in 6.21.1.
CVE-2026-53947: CWE-204: Observable Response Discrepancy in TryGhost Ghost
Description
Ghost, a Node.js content management system, has a vulnerability in its members signin endpoints from versions 5.18.0 up to but not including 6.21.1. This flaw allows an unauthenticated attacker to determine if an email address is registered on a Ghost site by observing differences in response behavior. The issue is classified as CWE-204 (Observable Response Discrepancy) and has a medium severity rating with a CVSS score of 5.3. The vulnerability is fixed starting in version 6.21.1.
CVSS v3.1
Score 5.3medium
Affected software
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-53947 describes an information disclosure vulnerability in Ghost CMS versions 5.18.0 through 6.21.0. The members signin endpoints respond differently depending on whether an email address is registered, enabling unauthenticated attackers to enumerate valid member emails. This is a classic observable response discrepancy issue (CWE-204). The vulnerability does not impact confidentiality beyond email enumeration, nor does it affect integrity or availability. The fix was introduced in version 6.21.1.
Potential Impact
An attacker can confirm the existence of specific email addresses registered as members on a Ghost site without authentication. This information disclosure can facilitate targeted phishing or social engineering attacks. There is no direct impact on data integrity or system availability.
Mitigation Recommendations
Upgrade Ghost to version 6.21.1 or later, where this vulnerability is fixed. Since no official patch or temporary workaround is detailed, applying the official fix is the recommended remediation. Patch status is confirmed by the vendor stating the fix is in 6.21.1.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-06-11T15:50:01.281Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a3c2387748d17fc4ff2f76c
Added to database: 06/24/2026, 18:35:51 UTC
Last enriched: 06/24/2026, 18:50:59 UTC
Last updated: 06/24/2026, 18:50:59 UTC
Views: 2
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