Deserialization of Untrusted Data Affecting pdfminer.six package, versions [,20251107)
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- published9 Nov 2025
- disclosed7 Nov 2025
- creditSuman Roy
Introduced: 7 Nov 2025
New CVE NOT AVAILABLE CWE-502 (opens in a new tab)How to fix?
Upgrade pdfminer.six to version 20251107 or higher.
Overview
pdfminer.six is a PDF parser and analyzer
Affected versions of this package are vulnerable to Deserialization of Untrusted Data via the CMap loading process. An attacker can execute arbitrary code with the privileges of the process running the library by placing a malicious .pickle.gz file in a directory included in the CMap search path.
Note: This is only exploitable if the attacker can write to a directory specified in the CMAP_PATH or the default CMap directories used by the process.
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.