CVE-2026-26980: Critical SQL Injection in Ghost CMS Exposes Databases to Unauthenticated Remote Attackers

Ghost CMS – Unauthenticated Database Arbitrary Read (SQL Injection)

Vulnerability Overview

CVE ID: CVE-2026-26980
Product: Ghost CMS
Vulnerability Type: SQL Injection (Improper Neutralization of Special Elements)
CWE: CWE-89
CVSS v3.1 Base Score: 9.4 (Critical)
Severity: Critical
Attack Vector: Network
Privileges Required: None
User Interaction: None
Attack Complexity: Low
Impact: Confidentiality – High | Integrity – Low | Availability – Low
Exploitability: Remote, unauthenticated
Public Exploit Availability: No verified weaponized exploit publicly released at time of analysis
Affected Versions: >= 3.24.0 and < 6.19.1
Patched Version: 6.19.1

Official Patch / Upgrade Link:
https://github.com/TryGhost/Ghost/releases/tag/v6.19.1

Technical Summary

A SQL injection vulnerability was identified in Ghost CMS within the Content API component responsible for handling slug-based ordering and filtering logic. The issue originated from improper construction of SQL queries when processing user-supplied slug values in Content API requests.

The Content API in Ghost is intentionally exposed publicly for retrieving posts and content. Because of this design, authentication is not required for many read operations. However, during query generation, parts of the ordering logic were dynamically constructed using string interpolation instead of parameterized query bindings.

As a result, specially crafted input supplied through filter parameters could manipulate the SQL query structure. This allowed arbitrary database read operations without authentication.

The issue was resolved by modifying the ordering logic to use parameterized bindings instead of raw string concatenation. Supporting libraries were also updated to ensure safe query handling.

Root Cause Analysis

The vulnerability was caused by:

Unsafe concatenation of user-controlled slug input into SQL ORDER BY clauses
Absence of strict validation on filter parameters
Lack of parameterized bindings in dynamic ordering logic
Public exposure of Content API endpoints by design

When malicious input was supplied inside filter expressions, it could alter SQL execution context. Since this occurred in read operations, exploitation primarily resulted in unauthorized database reads.

Affected Component

Ghost Content API
Slug-based filtering and ordering logic
Query builder responsible for orderByRaw functionality

Exploitation Details (Educational)

Attack Surface

Publicly accessible Content API endpoints
HTTP GET requests containing filter parameters
Slug-based ordering logic

Exploitation Conditions

The following conditions were required:

Target running a vulnerable Ghost version (< 6.19.1)
Content API publicly accessible (default configuration)
Database accessible through Ghost backend
No Web Application Firewall blocking malicious query patterns

What Could Be Extracted

Depending on database permissions and schema exposure:

User email addresses
Password hashes
API keys
Admin session tokens
Internal configuration values
Content drafts
Membership information

If database user privileges were overly permissive, impact could increase.

Proof of Concept (Educational)

No official exploit code was published by the vendor. However, the vulnerability type indicates it could be tested in a controlled lab environment by:

Sending Content API requests containing manipulated filter parameters
Observing abnormal query behavior
Testing for unexpected data returned in API responses

Exploitation Indicators

The following behaviors may indicate exploitation attempts:

Unusual filter= parameters in Content API requests
Encoded square brackets in query strings
Presence of SQL operators in URL parameters
Increased Content API traffic from single IP addresses
Unexpected large response sizes
Database slow query logs triggered by suspicious SELECT statements

Log Sources for Detection

Monitoring should include:

Web server access logs (NGINX / Apache)
Reverse proxy logs
WAF logs
Ghost application logs
Database query audit logs
API gateway logs
SIEM correlated events

Detection Rules

NGINX Log Detection

grep -E "filter=.*slug" /var/log/nginx/access.log

Suspicious Encoded Pattern Detection

grep -E "slug%3A%5B" /var/log/nginx/access.log

Apache Log Monitoring

grep -E "GET .*filter=.*slug" /var/log/apache2/access.log

Splunk Query – Suspicious Filter Abuse

index=web sourcetype=access_combined
| search uri_query="*filter=*"
| search uri_query="*slug:*" OR uri_query="*slug%3A%5B*"
| stats count by client_ip, uri_query, status
| where count > 5

Splunk Query – Large API Responses

index=web sourcetype=access_combined
| search uri_path="/ghost/api/content/*"
| stats avg(bytes) as avg_bytes, max(bytes) as max_bytes by client_ip
| where max_bytes > 500000

Elastic KQL

http.request.method: "GET" AND
url.path: "/ghost/api/content/*" AND
url.query: "*filter=*"

Refined detection:

url.query: "*slug:%5B*" OR url.query: "*slug:[*"

MySQL Suspicious Query Detection

SELECT * FROM mysql.general_log
WHERE argument LIKE '%ORDER BY%'
AND argument LIKE '%CASE%'
AND event_time > NOW() - INTERVAL 7 DAY;

PostgreSQL Log Inspection

grep "ORDER BY" postgresql.log | grep "CASE"

Behavioral Indicators

Repeated API calls with changing filter parameters
Use of SQL keywords inside URL parameters
Time delays in API responses (possible time-based injection testing)
HTTP 200 responses returning unexpected structured data

MITRE ATT&CK Mapping

T1190 – Exploit Public-Facing Application
T1041 – Exfiltration Over C2 Channel
T1005 – Data from Local System

Impact Assessment

Confidentiality

Severe impact. Arbitrary read access to database contents.

Integrity

Limited. Vulnerability primarily allowed read operations, not write manipulation.

Availability

Low direct impact. However, abuse could cause performance degradation.

Risk Evaluation

Because the Content API is public by design, this vulnerability significantly lowers the barrier to exploitation. No authentication was required. The exploit could be performed remotely over the internet.

Organizations running public Ghost instances were at high risk until patched.

Remediation

Immediate Actions

Upgrade Ghost CMS to version 6.19.1 or later
Restart Ghost service after upgrade
Clear cache and rebuild production assets

Official Upgrade Source

https://github.com/TryGhost/Ghost/releases/tag/v6.19.1

Temporary Mitigation (If Immediate Upgrade Not Possible)

Deploy WAF rule blocking suspicious slug filter patterns
Restrict Content API exposure via IP allowlist
Enable strict query logging
Monitor abnormal response sizes
Rate limit API requests

Post-Upgrade Validation

After upgrading:

Verify Ghost version using: ghost version
Confirm no raw SQL interpolation exists in custom modifications
Perform regression testing on Content API
Monitor logs for residual exploitation attempts

Incident Response Recommendations

If exploitation is suspected:

Review API logs for abnormal filter usage
Audit database access logs
Rotate admin credentials
Rotate API keys
Force password reset for privileged accounts
Conduct database integrity verification
Preserve logs for forensic analysis

Long-Term Security Recommendations

Always use parameterized queries in custom themes or integrations
Enable database audit logging
Deploy WAF with SQLi detection
Implement rate limiting on API endpoints
Restrict unnecessary API exposure
Regularly apply Ghost security updates
Conduct periodic penetration testing

Conclusion

CVE-2026-26980 represents a high-risk SQL injection vulnerability in Ghost CMS affecting the Content API. Because the endpoint was publicly accessible and required no authentication, exploitation could be performed remotely with minimal effort.

The vulnerability has been properly fixed in version 6.19.1 through the implementation of safe parameter binding in SQL query construction.

Immediate patching is strongly recommended. Detection monitoring should remain in place even after upgrading to identify scanning or exploitation attempts against legacy systems.