CVE-2026-28011: Yottis PHP File Inclusion Vulnerability

CVE-2026-28011 Overview

CVE-2026-28011 is a PHP Local File Inclusion (LFI) vulnerability affecting the ThemeREX Yottis WordPress theme through version 1.0.10. The flaw stems from improper control of filenames passed to PHP include or require statements [CWE-98]. Unauthenticated attackers can manipulate file path parameters to load arbitrary local PHP files on the server. Successful exploitation can lead to disclosure of sensitive configuration data, execution of attacker-controlled content, and full compromise of the underlying WordPress installation.

Critical Impact
Remote, unauthenticated attackers can include local files within the PHP execution context of the Yottis theme, threatening confidentiality, integrity, and availability of the WordPress host.

Affected Products

ThemeREX Yottis WordPress theme versions up to and including 1.0.10
WordPress installations bundling the vulnerable Yottis theme
Sites with Yottis installed but inactive may remain exploitable if theme files are reachable

Discovery Timeline

2026-03-05 - CVE-2026-28011 published to NVD
2026-04-22 - Last updated in NVD database

Technical Details for CVE-2026-28011

Vulnerability Analysis

The Yottis theme passes user-controlled input into a PHP include or require statement without sufficient validation or normalization. Because PHP resolves these statements against the local filesystem, an attacker who controls the filename argument can direct the interpreter to load files outside the intended template directory. Any PHP code within the loaded file is then executed under the privileges of the web server process.

The issue is categorized under [CWE-98], Improper Control of Filename for Include/Require Statement in PHP Program. While the CWE name references Remote File Inclusion, the advisory confirms exploitation results in Local File Inclusion against files already present on the host. The attack is reachable over the network without authentication, though it requires specific request conditions that increase exploitation complexity.

Root Cause

The root cause is missing allowlist validation on a filename parameter consumed by a PHP file inclusion sink. The theme accepts attacker-supplied input and concatenates it into an include path. Path traversal sequences and absolute paths are not filtered, allowing the interpreter to resolve arbitrary local resources.

Attack Vector

An attacker sends a crafted HTTP request to a vulnerable Yottis endpoint with a file path parameter pointing to a sensitive local file. The PHP runtime loads and executes the referenced file. If an attacker can first plant attacker-controlled content on the filesystem, for example via log poisoning or an upload feature, the LFI escalates into remote code execution. See the Patchstack Yottis Theme Vulnerability advisory for additional technical details.

Detection Methods for CVE-2026-28011

Indicators of Compromise

HTTP requests to Yottis theme paths containing traversal sequences such as ../ or encoded variants like %2e%2e%2f
Requests referencing sensitive local paths such as /etc/passwd, wp-config.php, or PHP session files in query parameters
Unexpected PHP processes spawning shells or outbound connections from the WordPress host
Web server access logs showing inclusion of log files or /proc/self/environ via theme parameters

Detection Strategies

Inspect web access logs for query parameters containing filesystem path patterns directed at /wp-content/themes/yottis/ resources
Apply web application firewall (WAF) rules that flag LFI signatures, including null byte and double-encoding evasions
Correlate inbound HTTP requests with subsequent file reads of WordPress configuration files using endpoint telemetry
Hunt for anomalous php-fpm or Apache child processes initiating network connections after suspicious theme requests

Monitoring Recommendations

Enable verbose PHP error logging to capture failed include or require attempts referencing unexpected paths
Monitor file integrity on theme directories to detect unauthorized modification of Yottis PHP files
Alert on access to wp-config.php or .env files outside of normal administrative workflows

How to Mitigate CVE-2026-28011

Immediate Actions Required

Disable or remove the Yottis theme on any WordPress site running version 1.0.10 or earlier until a fixed release is installed
Restrict access to /wp-content/themes/yottis/ via web server rules while remediation is in progress
Rotate WordPress secrets in wp-config.php, database credentials, and API keys if exploitation is suspected
Review web server and PHP-FPM logs for the last 90 days for inclusion-style request patterns

Patch Information

At the time of publication, the advisory lists all versions through 1.0.10 as affected and no fixed version is identified in the NVD record. Administrators should consult the Patchstack Yottis Theme Vulnerability advisory for the current patch status and upgrade to any vendor-released version above 1.0.10 once available.

Workarounds

Deploy WAF signatures that block path traversal and absolute path patterns in HTTP parameters targeting theme endpoints
Set PHP open_basedir to constrain file inclusion to the WordPress document root
Disable allow_url_include in php.ini to prevent escalation to remote file inclusion scenarios
Replace the Yottis theme with a maintained alternative if no vendor patch is forthcoming

bash

# Configuration example: harden php.ini and restrict theme access
# /etc/php/php.ini
allow_url_include = Off
allow_url_fopen = Off
open_basedir = "/var/www/html:/tmp"

# Apache: block direct execution of Yottis PHP files
<Directory "/var/www/html/wp-content/themes/yottis">
    <FilesMatch "\.php$">
        Require all denied
    </FilesMatch>
</Directory>