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.

No CVSS v4.0

No CVSS v3.1

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact High

Availability Impact Low

User Interaction Required

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
huggingface huggingface/transformers affected
Version Status Constraints
unspecified affected < 5.10.0

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Advisories

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Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/huggingface/transformers/commit/eaaaf8494dd5386634ae37d1d122212fdc315be5 cve-icon
https://huntr.com/bounties/362824d5-fe18-40e8-a6cf-62277f97a170 cve-icon
History

Sun, 02 Aug 2026 19:15:00 +0000

Type Values Removed Values Added
First Time appeared Huggingface
Huggingface transformers
Vendors & Products Huggingface
Huggingface transformers

Sun, 02 Aug 2026 15:45:00 +0000

Type Values Removed Values Added
Description 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.
Title Path Traversal in huggingface/transformers
Weaknesses CWE-22
References
Metrics cvssV3_0

{'score': 7.1, 'vector': 'CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:L'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: @huntr_ai

Published:

Updated: 2026-08-02T15:10:53.809Z

Reserved: 2026-05-28T15:41:24.076Z

Link: CVE-2026-9856

cve-icon Vulnrichment

No data.

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-02T19:00:04Z

Weaknesses