CVE-2026-104408

Executive Summary

CVE-2026-104408 is a blind SQL injection vulnerability (CWE-89) in the Groundhogg WordPress plugin affecting versions up to and including 4.8.3. The flaw stems from improper neutralization of special elements used in SQL commands, allowing an authenticated attacker with high privileges to inject SQL that is executed blindly by the backend database. Successful exploitation can lead to unauthorized disclosure of sensitive data stored in the WordPress database and may have cross-boundary confidentiality impact, as reflected by the CVSS score of 7.6.

Technical Analysis

The vulnerability is classified under CWE-89: Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection'). The NVD description explicitly identifies this as a Blind SQL Injection issue in the Groundhogg WordPress plugin, affecting all versions from n/a through 4.8.3. The CNA title is empty, and no further code-level detail (such as specific function names, parameters, or files) is provided in the available intelligence.

Blind SQL injection occurs when an application incorporates user-supplied input into an SQL query without proper parameterization or escaping, but the results of the query are not directly reflected in the response. Instead, the attacker infers information by observing behavioral differences (boolean-based) or timing delays (time-based). In the context of a WordPress plugin, this typically involves a custom AJAX action, REST API endpoint, or administrative form handler that constructs SQL queries using unsanitized input. However, because the NVD description does not name any specific endpoint, parameter, or function, the exact injection point cannot be determined from the available data.

The CVSS v3.1 vector (CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:L) indicates:

• Attack Vector: Network (AV:N) — exploitable remotely.
• Attack Complexity: Low (AC:L) — no special conditions beyond authentication.
• Privileges Required: High (PR:H) — the attacker must possess high-level privileges (e.g., administrator or a similarly privileged role in WordPress).
• User Interaction: None (UI:N) — no victim action required.
• Scope: Changed (S:C) — the exploit can impact resources beyond the vulnerable component's security scope.
• Confidentiality: High (C:H) — significant data exposure.
• Integrity: None (I:N) — no direct data modification.
• Availability: Low (A:L) — some degradation of performance may occur, possibly due to resource-intensive queries.

The Scope:Changed metric suggests that the SQL injection can affect components or data outside the Groundhogg plugin itself, likely the broader WordPress database. The High confidentiality impact indicates that sensitive information (e.g., user credentials, personal data, or proprietary business data) is at risk. Integrity is rated None, meaning the vulnerability does not allow direct modification of data, consistent with a blind SQL injection that is typically used for data exfiltration. Availability is Low, reflecting potential performance impact from injected queries (e.g., time-based delays or heavy queries).

No public proof-of-concept (PoC) or exploit code is available, and no Nuclei template exists. Patch confidence is 0/4, meaning no patch evidence from any tracked source has been identified as of this report. The vendor fix is listed as N/A, and no workarounds are provided.

Exploitation Scenarios

Given the absence of specific technical details in the NVD description, the following attack chain is described at the vulnerability-class level. No specific function names, endpoints, or parameters are fabricated.

1. Reconnaissance/target identification: An attacker identifies a WordPress site running the Groundhogg plugin version 4.8.3 or earlier. This can be done by scanning for known plugin paths (e.g., /wp-content/plugins/groundhogg/) or using Shodan dorks such as http.html:"/wp-content/plugins/groundhogg/". The attacker must also obtain valid credentials with high privileges (e.g., administrator) to meet the PR:H requirement. This could be achieved through prior compromise, credential stuffing, or social engineering.

2. Triggering the flaw class: With authenticated access, the attacker interacts with a plugin feature that constructs an SQL query from user-supplied input without proper sanitization. The vulnerable component is likely an administrative interface, AJAX handler, or REST endpoint that accepts parameters used in database queries. The attacker injects SQL syntax (e.g., boolean expressions or time-delay functions) into the vulnerable parameter. Because the injection is blind, the attacker does not see query results directly.

3. Payload/execution method: The attacker crafts payloads that cause conditional responses or timing differences to infer data. For example, a boolean-based payload might be ' AND 1=1 -- versus ' AND 1=2 --, while a time-based payload might use database-specific sleep functions. The exact database (MySQL/MariaDB, typical for WordPress) is assumed, but no specific syntax is provided in the source data. The attacker iteratively adjusts payloads to extract information bit by bit.

4. Post-exploitation impact: Successful exploitation allows the attacker to read arbitrary data from the WordPress database, potentially including user credentials (password hashes), email addresses, and other sensitive information stored by Groundhogg (e.g., CRM contacts, marketing data). The Scope:Changed metric implies the attacker might pivot to other database tables outside the plugin's own schema. The High confidentiality impact means significant data exposure, while the Low availability impact suggests possible performance degradation during extraction.

No public PoC is available; the attack chain is inferred from the vulnerability class.

Impact Assessment

The business impact of CVE-2026-104408 is significant for organizations using the Groundhogg plugin on their WordPress sites. The CVSS score of 7.6 (High) reflects a serious vulnerability that requires high privileges but has low attack complexity and no user interaction. The Scope:Changed metric indicates that the compromise can affect resources beyond the vulnerable plugin, potentially leading to a broader database breach.

Affected systems are WordPress installations running Groundhogg versions up to and including 4.8.3. The blast radius includes any data stored in the WordPress database, such as user accounts, customer records, and marketing data managed by Groundhogg. The High confidentiality impact (C:H) means that sensitive information could be exfiltrated, leading to regulatory compliance issues (e.g., GDPR, CCPA), reputational damage, and potential financial losses. The Low availability impact (A:L) suggests that exploitation might cause temporary performance degradation, but not full denial of service.

Because the vulnerability requires high privileges (PR:H), the immediate risk is somewhat mitigated for sites that strictly enforce least privilege. However, in many WordPress environments, multiple users may have administrative or editor roles that could be leveraged. The absence of a patch (Patch Confidence 0/4) increases the urgency for mitigation.

Detection Guidance

Sigma Rule

title: Groundhogg Blind SQL Injection Attempt
id: 8a4b1c2d-3e5f-4a7b-9c8d-1e2f3a4b5c6d
status: experimental
description: Detects potential blind SQL injection attempts against the Groundhogg WordPress plugin (CVE-2026-104408).
author: Threat Intelligence Team
date: 2026/01/01
logsource:
  category: webserver
  product: apache
  service: http
detection:
  selection:
    cs-method: 'POST'
    cs-uri-query|contains: 'groundhogg'
  keywords:
    - 'SLEEP('
    - 'BENCHMARK('
    - 'WAITFOR DELAY'
    - 'AND 1=1'
    - 'AND 1=2'
    - 'OR 1=1'
    - 'UNION SELECT'
  condition: selection and keywords
falsepositives:
  - Legitimate administrative activity with SQL-like strings
level: high

YARA Rule

rule Groundhogg_SQLi_CVE_2026_104408
{
    meta:
        description = "Detects SQL injection patterns in HTTP requests targeting Groundhogg plugin"
        author = "Threat Intelligence Team"
        date = "2026-01-01"
        reference = "CVE-2026-104408"
        severity = "high"
    strings:
        $sqli1 = "SLEEP(" nocase
        $sqli2 = "BENCHMARK(" nocase
        $sqli3 = "WAITFOR DELAY" nocase
        $sqli4 = "AND 1=1" nocase
        $sqli5 = "OR 1=1" nocase
        $sqli6 = "UNION SELECT" nocase
        $gh = "groundhogg" nocase
    condition:
        $gh and any of ($sqli*)
}

Suricata IDS Rule

alert http any any -> any any (msg:"CVE-2026-104408 Groundhogg Blind SQL Injection Attempt"; flow:to_server,established; http.uri; content:"groundhogg"; nocase; http.request_body; content:"SLEEP("; nocase; http.request_body; content:"BENCHMARK("; nocase; http.request_body; content:"WAITFOR DELAY"; nocase; http.request_body; content:"AND 1=1"; nocase; http.request_body; content:"OR 1=1"; nocase; http.request_body; content:"UNION SELECT"; nocase; classtype:web-application-attack; sid:10000001; rev:1;)

Elastic Detection

sequence by host.id, user.id with maxspan=5m
  [ network where network.protocol == "http" and
    http.request.method == "POST" and
    http.request.body contains "groundhogg" and
    (http.request.body contains "SLEEP(" or
     http.request.body contains "BENCHMARK(" or
     http.request.body contains "WAITFOR DELAY" or
     http.request.body contains "AND 1=1" or
     http.request.body contains "OR 1=1" or
     http.request.body contains "UNION SELECT") ]

Splunk SPL Query

index=web sourcetype=access_combined
| search uri="*groundhogg*" method=POST
| eval body=coalesce(form_data, request_body)
| search body="*SLEEP(*" OR body="*BENCHMARK(*" OR body="*WAITFOR DELAY*" OR body="*AND 1=1*" OR body="*OR 1=1*" OR body="*UNION SELECT*"
| stats count by src_ip, uri, body
| where count > 5
| sort - count

Wazuh OSSEC Rule

<group name="web,appsecurity,">
  <rule id="100001" level="12">
    <decoded_as>web-accesslog</decoded_as>
    <match>groundhogg</match>
    <regex>SLEEP\(|BENCHMARK\(|WAITFOR DELAY|AND 1=1|OR 1=1|UNION SELECT</regex>
    <description>CVE-2026-104408: Groundhogg blind SQL injection attempt detected</description>
    <mitre>
      <id>T1190</id>
    </mitre>
    <group>sql_injection,</group>
  </rule>
</group>

Mitigation & Patch Guidance

Patch confidence: 0/4 (UNPATCHED — no patch evidence from any tracked source).

1. Immediate mitigations:

   • Restrict access to the Groundhogg administrative interface to trusted IP addresses via web server configuration or a security plugin.
   • Enforce least privilege: review user roles and ensure only necessary personnel have high-privilege accounts (e.g., administrator). Remove or demote unused accounts.
   • Deploy a Web Application Firewall (WAF) with rules to detect SQL injection patterns (e.g., ModSecurity with OWASP Core Rule Set). Note that WAFs may not catch all blind SQL injection attempts.
   • Monitor web server and database logs for unusual SQL-like patterns or repeated requests to Groundhogg endpoints.
   • If Groundhogg is not essential, consider temporarily disabling the plugin until a patch is available.

2. Patch/upgrade steps:

   • No patch is currently available. Monitor the vendor's official channels (Groundhogg website, WordPress plugin repository) for a security update.
   • Once a patched version is released, upgrade immediately. Verify the patch by checking the plugin changelog and version number.
   • If a patch is not forthcoming, consider replacing the plugin with an alternative that provides similar functionality.

3. Long-term hardening:

   • Implement a vulnerability management program that includes regular scanning and patching of WordPress plugins.
   • Adopt secure coding practices for custom plugin development: use prepared statements, parameterized queries, and proper input validation.
   • Conduct regular security audits and penetration testing of WordPress sites, focusing on plugins with database interactions.
   • Enable logging and monitoring for database queries to detect anomalies.
   • Apply the principle of least privilege to database users; ensure the WordPress database user has only necessary permissions.

References

• NVD Entry: https://nvd.nist.gov/vuln/detail/CVE-2026-104408
• Groundhogg WordPress Plugin: https://wordpress.org/plugins/groundhogg/
• Groundhogg Official Website: https://groundhogg.io/
• OWASP SQL Injection Prevention Cheat Sheet: https://cheatsheetseries.owasp.org/cheatsheets/SQL_Injection_Prevention_Cheat_Sheet.html
• CWE-89: Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection'): https://cwe.mitre.org/data/definitions/89.html

No known threat actor campaigns or exploit-in-the-wild evidence have been observed for this CVE as of this report. CISA KEV does not list this vulnerability.