Deserialization of Untrusted Data Affecting pontedilana/php-weasyprint package, versions <2.6.0
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- published23 Jun 2026
- disclosed19 Jun 2026
- creditUnknown
Introduced: 19 Jun 2026
CVE-2026-49286 (opens in a new tab)How to fix?
Upgrade pontedilana/php-weasyprint to version 2.6.0 or higher.
Overview
pontedilana/php-weasyprint is a PHP library allowing PDF generation from an url or a html page.
Affected versions of this package are vulnerable to Deserialization of Untrusted Data in the prepareOutput() method of src/AbstractGenerator.php, whose strpos($filename, 'phar://') guard is case sensitive even though PHP stream wrappers are not. An attacker can achieve remote code execution by passing an output filename with a case-altered scheme such as PHAR:// to generate() or generateFromHtml(), which bypasses the guard, reaches fileExists(), and deserializes the metadata of a PHAR archive placed on the filesystem through an available gadget chain. Exploitation requires control of the output filename, the ability to place a PHAR archive on the server, a usable gadget chain in the loaded code, and PHP 7.x.
Details
Serialization is a process of converting an object into a sequence of bytes which can be persisted to a disk or database or can be sent through streams. The reverse process of creating object from sequence of bytes is called deserialization. Serialization is commonly used for communication (sharing objects between multiple hosts) and persistence (store the object state in a file or a database). It is an integral part of popular protocols like Remote Method Invocation (RMI), Java Management Extension (JMX), Java Messaging System (JMS), Action Message Format (AMF), Java Server Faces (JSF) ViewState, etc.
Deserialization of untrusted data (CWE-502) is when the application deserializes untrusted data without sufficiently verifying that the resulting data will be valid, thus allowing the attacker to control the state or the flow of the execution.