- Compatible XF Versions
 - 2.3
 
- Visible Branding
 - No
 
Security Fix
Today we are advising all customers running XenForo that a potential security vulnerability has been identified. All affected customers should either upgrade to XenForo 2.1.15 or XenForo 2.2.16.If you are a XenForo Cloud customer, a fix has been rolled out automatically, and no further action is required to address this issue.
If you are running a pre-release version of XenForo 2.3, you should follow the instructions in the announcement thread for the XenForo 2.3.0 Release Candidate 1 release.
The issue relates to a potential cross-site request forgery and code injection vulnerability which could lead to a remote code execution (RCE) or cross-site scripting (XSS) exploit.
XenForo extends thanks to independent security researcher, Egidio Romano (EgiX), working with SSD Secure Disclosure.
We recommend doing a full upgrade to resolve the issue, but a patch can be applied manually to any version. See below for further details.
Applying a patch manually
To patch this issue manually you will need to edit one file manually and upload some changed files.Step 1: Edit src/XF.php
Find the following line in this file:
		PHP:
	
	$parts = explode(':', $string, 3);
	
		PHP:
	
	        if (!$string) return '';
        if (strpos($string, ':') === false)
        {
            $pattern = '#^\\\?'
                . str_replace('%s', '([A-Za-z0-9_\\\]+)', preg_quote(ltrim($formatter, '\\')))
                . '$#';
            if (!preg_match($pattern, $string, $matches))
            {
                throw new \InvalidArgumentException(sprintf(
                    'Class %s does not match formatter pattern %s',
                    $string,
                    $formatter
                ));
            }
            // already a class
            return $string;
        }
        $parts = explode(':', $string, 3);
	Note: This file cannot be patched automatically as it contains install-specific data. You must apply this change manually to any XenForo installation running XenForo 2.1 or 2.2 to effectively fix the issue.
Step 2: Upload XF files
- Download either 
2115-patch.zip(for XenForo 2.1) or2216-patch.zip(for XenForo 2.2). - Extract the .zip file
 - Upload the contents of the upload directory to the root of your XenForo installation
 
Step 3: Upload XFMG files (for XenForo Media Gallery customers only)
- Download either 
xfmg219-patch.zip(for XenForo Media Gallery 2.1) orxfmg226-patch.zip(for XenForo Media Gallery 2.2). - Extract the .zip file
 - Upload the contents of the 
uploaddirectory to the root of your XenForo installation