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CVE-2026-9856

CVE-2026-9856 · Path Traversal in huggingface/transformers

This page contains facts from public vulnerability sources. Check the original advisory before updating.

A vulnerability in huggingface/transformers versions <=5.8.0.dev0 allows an attacker to perform arbitrary file writes via path traversal. The issue resides in the `save_pretrained()` methods of `PreTrainedTokenizerBase` and `ProcessorMixin`, where keys from the `chat_template` dictionary are used directly as filenames without proper validation. An attacker can exploit this by publishing a malicious Hugging Face Hub repository with a crafted `tokenizer_config.json` file. When a victim downloads and saves the tokenizer or processor, the attacker-controlled keys can escape the intended save directory, enabling arbitrary file writes with attacker-controlled content. This vulnerability affects multiple processors inheriting from `ProcessorMixin`, including Idefics, Florence, Gemma, Phi, and Qwen-VL.

CVSS 7.1 · High · EPSS 0.5% · Fix available

Published
Updated

Stack: python

Affected products and versions

  • huggingface/transformers

    Versions
    • ≥ unspecified, < 5.10.0: Affected (custom)

    Update to 5.10.0

  • transformers PyPI

    Versions
    • 0.1
    • 2.0.0
    • 2.1.0
    • 2.1.1
    • 2.10.0
    • 2.11.0
    • 2.2.0
    • 2.2.1
    • 2.2.2
    • 2.3.0
    • 2.4.0
    • 2.4.1
    • 2.5.0
    • 2.5.1
    • 2.6.0
    • 2.7.0
    • 2.8.0
    • 2.9.0
    • 2.9.1
    • 3.0.0
    • 3.0.1
    • 3.0.2
    • 3.1.0
    • 3.2.0
    • 3.3.0
    • 3.3.1
    • 3.4.0
    • 3.5.0
    • 3.5.1
    • 4.0.0
    • 4.0.0rc1
    • 4.0.1
    • 4.1.0
    • 4.1.1
    • 4.10.0
    • 4.10.1
    • 4.10.2
    • 4.10.3
    • 4.11.0
    • 4.11.1
    • 4.11.2
    • 4.11.3
    • 4.12.0
    • 4.12.1
    • 4.12.2
    • 4.12.3
    • 4.12.4
    • 4.12.5
    • 4.13.0
    • 4.14.0
    • 4.14.1
    • 4.15.0
    • 4.16.0
    • 4.16.1
    • 4.16.2
    • 4.17.0
    • 4.18.0
    • 4.19.0
    • 4.19.1
    • 4.19.2
    • 4.19.3
    • 4.19.4
    • 4.2.0
    • 4.2.1
    • 4.2.2
    • 4.20.0
    • 4.20.1
    • 4.21.0
    • 4.21.1
    • 4.21.2
    • 4.21.3
    • 4.22.0
    • 4.22.1
    • 4.22.2
    • 4.23.0
    • 4.23.1
    • 4.24.0
    • 4.25.0
    • 4.25.1
    • 4.26.0
    • 4.26.1
    • 4.27.0
    • 4.27.1
    • 4.27.2
    • 4.27.3
    • 4.27.4
    • 4.28.0
    • 4.28.1
    • 4.29.0
    • 4.29.1
    • 4.29.2
    • 4.3.0
    • 4.3.0rc1
    • 4.3.1
    • 4.3.2
    • 4.3.3
    • 4.30.0
    • 4.30.1
    • 4.30.2
    • 4.31.0
    • 4.32.0
    • 4.32.1
    • 4.33.0
    • 4.33.1
    • 4.33.2
    • 4.33.3
    • 4.34.0
    • 4.34.1
    • 4.35.0
    • 4.35.1
    • 4.35.2
    • 4.36.0
    • 4.36.1
    • 4.36.2
    • 4.37.0
    • 4.37.1
    • 4.37.2
    • 4.38.0
    • 4.38.1
    • 4.38.2
    • 4.39.0
    • 4.39.1
    • 4.39.2
    • 4.39.3
    • 4.4.0
    • 4.4.1
    • 4.4.2
    • 4.40.0
    • 4.40.1
    • 4.40.2
    • 4.41.0
    • 4.41.1
    • 4.41.2
    • 4.42.0
    • 4.42.1
    • 4.42.2
    • 4.42.3
    • 4.42.4
    • 4.43.0
    • 4.43.1
    • 4.43.2
    • 4.43.3
    • 4.43.4
    • 4.44.0
    • 4.44.1
    • 4.44.2
    • 4.45.0
    • 4.45.1
    • 4.45.2
    • 4.46.0
    • 4.46.1
    • 4.46.2
    • 4.46.3
    • 4.47.0
    • 4.47.1
    • 4.48.0
    • 4.48.1
    • 4.48.2
    • 4.48.3
    • 4.49.0
    • 4.5.0
    • 4.5.1
    • 4.50.0
    • 4.50.1
    • 4.50.2
    • 4.50.3
    • 4.51.0
    • 4.51.1
    • 4.51.2
    • 4.51.3
    • 4.52.0
    • 4.52.1
    • 4.52.2
    • 4.52.3
    • 4.52.4
    • 4.53.0
    • 4.53.1
    • 4.53.2
    • 4.53.3
    • 4.54.0
    • 4.54.1
    • 4.55.0
    • 4.55.1
    • 4.55.2
    • 4.55.3
    • 4.55.4
    • 4.56.0
    • 4.56.1
    • 4.56.2
    • 4.57.0
    • 4.57.1
    • 4.57.2
    • 4.57.3
    • 4.57.4
    • 4.57.5
    • 4.57.6
    • 4.6.0
    • 4.6.1
    • 4.7.0
    • 4.8.0
    • 4.8.1
    • 4.8.2
    • 4.9.0
    • 4.9.1
    • 4.9.2
    • 5.0.0
    • 5.0.0rc0
    • 5.0.0rc1
    • 5.0.0rc2
    • 5.0.0rc3
    • 5.1.0
    • 5.2.0
    • 5.3.0
    • 5.4.0
    • 5.5.0
    • 5.5.1
    • 5.5.2
    • 5.5.3
    • 5.5.4
    • 5.6.0
    • 5.6.1
    • 5.6.2
    • 5.7.0
    • 5.8.0
    • 5.8.1
    • 5.9.0
    Affected ranges
    • ECOSYSTEM: < 5.10.0

    Update to 5.10.0

Original sources

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