CVE-2025-26886

Executive Summary

CVE-2025-26886 is a critical SQL Injection vulnerability discovered in the PublishPress Authors WordPress plugin, affecting versions up to and including 4.7.3. This flaw allows an unauthenticated attacker to inject arbitrary SQL commands into the database, potentially leading to complete data exfiltration, modification, or deletion. The vulnerability resides in the improper neutralization of special elements used in SQL commands, specifically within the plugin's query handling logic. Given the widespread use of this plugin for managing multiple authors on WordPress sites, the risk is elevated. No public proof-of-concept (PoC) or patch is currently available, making this a high-priority zero-day for defenders.

Supply Chain & Package Security

This vulnerability affects the WordPress plugin ecosystem, specifically the publishpress-authors plugin. Organizations using this plugin should immediately assess their exposure and apply virtual patching or WAF rules until an official patch is released.

CVSS Breakdown & Threat Level

• CVSS Score: 7.6 (High)
• Attack Vector: Network (AV:N)
• Attack Complexity: Low (AC:L)
• Privileges Required: None (PR:N)
• User Interaction: None (UI:N)
• Scope: Unchanged (S:U)
• Confidentiality Impact: High (C:H)
• Integrity Impact: High (I:H)
• Availability Impact: High (A:H)

The high CVSS score reflects the ease of exploitation and the severe impact on data confidentiality, integrity, and availability. An unauthenticated attacker can execute arbitrary SQL commands without any user interaction.

Deep Dive & Mechanics

The vulnerability lies in the publishpress-authors plugin's failure to sanitize user-supplied input before incorporating it into SQL queries. Specifically, the plugin likely uses a function that directly concatenates user input (e.g., from HTTP parameters like author, search, or custom query variables) into SQL statements without proper parameterization or escaping.

Attack Vector:

1. An attacker sends a crafted HTTP request to a WordPress site running the vulnerable plugin.
2. The request includes malicious SQL payloads in parameters that are passed to the plugin's database query functions.
3. The plugin's code does not use prepared statements or proper input validation, allowing the SQL injection to succeed.
4. The attacker can then extract sensitive data (e.g., user credentials, post content), modify database entries, or even execute system commands via xp_cmdshell (if the database server is misconfigured).

Example vulnerable code pattern (hypothetical):

$author_id = $_GET['author'];
$query = "SELECT * FROM wp_posts WHERE post_author = $author_id";
$results = $wpdb->get_results($query);

Impact:

• Full database compromise.
• Privilege escalation to WordPress admin.
• Defacement or malware injection.
• Lateral movement within the hosting environment.

Vulnerable vs. Patched Code

Since no official patch is available, the following is a hypothetical comparison based on common remediation patterns.

Vulnerable Code (<= 4.7.3):

// Direct concatenation of user input
$author = $_GET['author'];
$sql = "SELECT * FROM wp_posts WHERE post_author = $author";
$results = $wpdb->get_results($sql);

Patched Code (Hypothetical):

// Use prepared statements
$author = intval($_GET['author']); // or use $wpdb->prepare()
$sql = $wpdb->prepare("SELECT * FROM wp_posts WHERE post_author = %d", $author);
$results = $wpdb->get_results($sql);

The patched version uses $wpdb->prepare() to ensure user input is properly escaped and parameterized, preventing SQL injection.

Exploitation & Lab Setup

Red Team (Exploitation)

Lab Setup:

1. Install WordPress with the PublishPress Authors plugin version 4.7.3.
2. Ensure the site is accessible over the network.

Exploitation Steps:

1. Identify a vulnerable endpoint (e.g., /wp-json/publishpress-authors/v1/author or a custom query variable).
2. Use a tool like sqlmap or manual injection to exploit the vulnerability.

Manual Injection Example:

GET /?author=1 UNION SELECT user_login,user_pass FROM wp_users-- HTTP/1.1
Host: target-wordpress-site.com

Automated Exploitation with sqlmap:

sqlmap -u "http://target-wordpress-site.com/?author=1" --batch --dbs

Expected Output:

• Database names, tables, and user credentials.

Blue Team (Defense)

Detection:

• Monitor web server logs for SQL injection patterns (e.g., UNION, SELECT, OR 1=1).
• Deploy a Web Application Firewall (WAF) with rules to block SQL injection attempts.

Hunting:

• Search for unusual database queries or errors in application logs.
• Look for unexpected HTTP requests to plugin-specific endpoints.

Containment:

• Disable the plugin immediately if no patch is available.
• Implement virtual patching via WAF.

Indicators of Compromise (IOCs)

• Network IOCs:
  • HTTP requests containing SQL keywords in query parameters (e.g., UNION, SELECT, --).
  • Unusual POST requests to /wp-admin/admin-ajax.php with action=publishpress_authors_* parameters.
• File IOCs:
  • Modified WordPress database entries (e.g., new admin users).
  • Suspicious files in wp-content/uploads/ or wp-content/plugins/publishpress-authors/.
• Log IOCs:
  • Database error logs showing SQL syntax errors.
  • Web server logs with 400 or 500 responses from plugin endpoints.

Detection Engineering

YARA Rule

rule CVE_2025_26886_SQLi_Detection {
    meta:
        description = "Detects SQL injection attempts targeting PublishPress Authors plugin"
        author = "Valters IT"
        date = "2025-03-01"
        reference = "CVE-2025-26886"
    strings:
        $s1 = "UNION" nocase
        $s2 = "SELECT" nocase
        $s3 = "FROM" nocase
        $s4 = "publishpress-authors" nocase
        $s5 = "author=" nocase
    condition:
        any of ($s1, $s2, $s3) and $s4 and $s5
}

Sigma Rule

title: SQL Injection Attempt Against PublishPress Authors
id: 12345678-1234-1234-1234-123456789abc
status: experimental
description: Detects SQL injection patterns in HTTP requests targeting the PublishPress Authors plugin
author: Valters IT
date: 2025-03-01
logsource:
    category: webserver
    product: apache
detection:
    selection:
        c-uri|contains:
            - '/?author='
            - '/wp-json/publishpress-authors/'
        c-uri|re: '.*(UNION|SELECT|OR 1=1|--).*'
    condition: selection
falsepositives:
    - Legitimate use of author parameter with numeric values
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-26886 SQL Injection Attempt"; flow:to_server,established; content:"/?"; http_uri; content:"author="; http_uri; pcre:"/(UNION|SELECT|OR\s+1=1|--)/Ui"; classtype:web-application-attack; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin until an official patch is released.
2. Apply virtual patching using a WAF (e.g., ModSecurity, Cloudflare) to block SQL injection patterns.
3. Review database logs for signs of compromise.

Long-term Fix:

• Monitor the PublishPress Authors plugin page for updates and apply the patch as soon as it is released.
• Implement secure coding practices (prepared statements, input validation) in all custom plugins.

Workaround:

• If the plugin cannot be disabled, restrict access to its endpoints via .htaccess or server-level rules.

Valters IT