Deserialization of Untrusted Data Affecting pdfminer.six package, versions [,20251107)

pdfminer.six is a PDF parser and analyzer

Affected versions of this package are vulnerable to Deserialization of Untrusted Data via the CMapDB._load_data function. An attacker can execute arbitrary code by crafting a malicious PDF that references a specially crafted pickle file, which is then deserialized without proper validation.

Notes:

• Exploitation of this vulnerability requires an attacker to provide a remote reference to a malicious pickle file at a location accessible to the target system.
• On Linux-like systems, only files on the filesystem can be resolved, requiring the malicious file to be present on the target system in a location that the attacker already knows
• On Windows, the malicious file path can include network locations, e.g., WebDAV, SMB.

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.

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