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CVE-2025-64512 — pdfminer.six vulnerable to Arbitrary Code Execution via Crafted PDF Input

2026-09-29T12:10:50.614377+00:00

Affected: pdfminer.six

Pdfminer.six is a community maintained fork of the original PDFMiner, a tool for extracting information from PDF documents. Prior to version 20251107, pdfminer.six will execute arbitrary code from a malicious pickle file if provided with a malicious PDF file. The `CMapDB._load_data()` function in pdfminer.six uses `pickle.loads()` to deserialize pickle files. These pickle files are supposed to be part of the pdfminer.six distribution stored in the `cmap/` directory, but a malicious PDF can specify an alternative directory and filename as long as the filename ends in `.pickle.gz`. A malicious, zipped pickle file can then contain code which will automatically execute when the PDF is processed. Version 20251107 fixes the issue.

GHSA-wf5f-4jwr-ppcp — Arbitrary Code Execution in pdfminer.six via Crafted PDF Input

2026-09-29T12:10:50.614543+00:00

Affected: PyPI: pdfminer.six

### Summary

pdfminer.six will execute arbitrary code from a malicious pickle file if provided with a malicious PDF file. The `CMapDB._load_data()` function in pdfminer.six uses `pickle.loads()` to deserialize pickle files. These pickle files are supposed to be part of the pdfminer.six distribution stored in the `cmap/` directory, but a malicious PDF can specify an alternative directory and filename as long as the filename ends in `.pickle.gz`. A malicious, zipped pickle file can then contain code which will automatically execute when the PDF is processed.

### Details

```python # Vulnerable code in pdfminer/cmapdb.py:233-246 def _load_data(cls, name: str) -> Any: name = name.replace("\0", "") # Insufficient sanitization filename = "%s.pickle.gz" % name # ... path construction ... path = os.path.join(directory, filename) # If filename is an absolte path, directory is ignored # ... return type(str(name), (), pickle.loads(gzfile.read())) # Unsafe deserialization ```

An attacker can: 1. Create a malicious PDF with a CMap reference like `/malicious` 2. Place a malicious pickle file at `/malicious.pickle.gz` 3. When the PDF is processed, pdfminer loads and deserializes the malicious pickle 4. The pickle deserialization can execute arbitrary Python code

### POC

#### Malicious PDF

Create a PDF with a malicious CMAP entry:

``` 5 0 obj << /Type /Font /Subtype /Type0 /BaseFont /MaliciousFont-Identity-H /Encoding /#2Fpdfs#2Fmalicious /DescendantFonts [6…

PYSEC-2026-1762 — Arbitrary Code Execution in pdfminer.six via Crafted PDF Input