CVE-2026-9856Path Traversal in huggingface/transformers
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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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 (v3.0, CNA)CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:L
- Weakness (CWE)
- CWE-22
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- @huntr_ai
- NVD analysis
- Awaiting Analysis
- Record last updated
- Aug 3, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
huggingface huggingface/transformers huggingface:transformers (from the name) | from unspecified before 5.10.0 | CNA record |
References
- https://huntr.com/bounties/362824d5-fe18-40e8-a6cf-62277f97a170
- https://github.com/huggingface/transformers/commit/eaaaf8494dd5386634ae37d1d122212fdc315be5
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.