Joomla! <= 4.1.0 (Tar.php) Zip Slip Vulnerability

• Software Link:

• Affected Versions:

Version 4.1.0 and prior versions.
Version 3.10.6 and prior versions.

• Vulnerability Description:

The vulnerability is located in the /libraries/vendor/joomla/archive/src/Tar.php script. Specifically, into the Joomla\Archive\Tar::extract() method:


		for ($i = 0, $n = \count($this->metadata); $i < $n; $i++)
			$type = strtolower($this->metadata[$i]['type']);

			if ($type == 'file' || $type == 'unix file')
				$buffer = $this->metadata[$i]['data'];
				$path   = Path::clean($destination . '/' . $this->metadata[$i]['name']);

				// Make sure the destination folder exists
				if (!Folder::create(\dirname($path)))
					throw new \RuntimeException('Unable to create destination folder ' . \dirname($path));

				if (!File::write($path, $buffer))
					throw new \RuntimeException('Unable to write entry to file ' . $path);

The vulnerability exists because the above code is using the filename within the Tar archive ($path variable created at line 122) to write the extracted file by using File::write() at line 130, without properly verifying the destination path. This could be exploited to carry out Zip Slip (or Path Traversal) attacks and write/overwrite arbitrary files, potentially resulting in execution of arbitrary PHP code or other dangerous impacts. In the Joomla! core, successful exploitation of this vulnerability would require administrator privileges. However, there could be third-party components using the Joomla\Archive\Archive::extract() method. In such cases, this might potentially be exploited also by unauthenticated attackers, depending on the context.

• Solution:

Upgrade to version 3.10.7, 4.1.1, or later.

• Disclosure Timeline:

[19/02/2021] – Vendor notified
[21/02/2021] – Vulnerability acknowledged by the vendor
[21/02/2021] – Vendor sent details about a proposed patch
[21/02/2021] – Sent feedback about the patch correctness
[29/03/2022] – Vendor update released
[29/03/2022] – Public disclosure

• CVE Reference:

The Common Vulnerabilities and Exposures project (
has assigned the name CVE-2022-23793 to this vulnerability.

• Credits:

Vulnerability discovered by Egidio Romano.

• Other References: