gcdRadar
archive/Patch now/AIR-2026-0872
closedclosed 2 Aug 2026Patch now2 Disclosed vulnerabilityAI

Hugging Face Transformers save_pretrained allows arbitrary file writes

Transformers

A vulnerability in Hugging Face Transformers permits arbitrary file writes via path traversal in chat template names during model saving. Malicious repositories can exploit tokenizer configurations to write files outside intended directories.

disclosed CVENo confirmed exploitation, so this record is tracked as a disclosed vulnerability and not counted as an incident. It moves into the counts if CISA or the vendor confirms exploitation. Why

CVSS
7.1
EPSS
<0.01 · top 60% · 2026-11-13
EPSS scores by FIRST
fix status
Fix status unknown
first report
2 Aug 2026
last update
2 Aug 2026
CVE ids
CVE-2026-9856other records

Timeline · 1

  1. 2 Aug 2026CVE-2026-9856: Transformers save_pretrained path traversal allows arbitrary file writes through chat template names

Sources · 1

Advisories and databases

  1. 2026-08-02
    CVE-2026-9856: Transformers save_pretrained path traversal allows arbitrary file writes through chat template names
    GitHub Advisory Database · github.com/advisories/GHSA-xrqw-3rrv-vx5w

Titles and links belong to their publishers. The summary above is written by gcdRadar in its own words; data is CC BY-SA 4.0.

Classification

lane
Patch now
AI role
Attack on AI
categories
Infrastructure vulnerabilitySupply chain
severity
2 · Disclosed vulnerability
fix status
Fix status unknown
targets
Framework / tooling
owasp llm top 10
LLM03:2025 Supply Chain
mitre atlas
AML.T0010 AI Supply Chain Compromise
tags
transformerspath-traversal
dates
happened 2 Aug 2026 · first reported 2 Aug 2026
origin
GitHub Advisory Database
Vulnerability record from NVD / the GitHub Advisory Database. This product uses the NVD API but is not endorsed or certified by the NVD.
record
confidence 0.95 · created 2026-10-18 07:00Z · updated 2026-10-18 07:00Z

Lane, AI role, categories and severity come from the classifier; the OWASP and ATLAS rows are derived from the categories. How these are assigned

Copy a brief

This record as a short Markdown brief, for a ticket, a chat or a coding agent.

the brief as text
# Hugging Face Transformers save_pretrained allows arbitrary file writes

https://gcdradar.vercel.app/incidents/hugging-face-transformers-save-pretrained-allows-arbitrary-f · AIR-2026-0872 · closed 2026-08-02

- Lane: Patch now
- Severity: 2 (Disclosed vulnerability)
- Fix status: Fix status unknown
- First reported: 2026-08-02
- AI role: Attack on AI
- Products: Transformers
- CVE ids: CVE-2026-9856
- CVSS: 7.1

## Summary

A vulnerability in Hugging Face Transformers permits arbitrary file writes via path traversal in chat template names during model saving. Malicious repositories can exploit tokenizer configurations to write files outside intended directories.

## What to do

No action recorded; read the sources below and the vendor's advisory.

## Latest updates

- 2026-08-02: CVE-2026-9856: Transformers save_pretrained path traversal allows arbitrary file writes through chat template names (https://github.com/advisories/GHSA-xrqw-3rrv-vx5w)

## Sources

- 2026-08-02 GitHub Advisory Database: CVE-2026-9856: Transformers save_pretrained path traversal allows arbitrary file writes through chat template names https://github.com/advisories/GHSA-xrqw-3rrv-vx5w

Verify against the vendor's advisory before changing production. Data CC BY-SA 4.0, https://gcdradar.vercel.app.

Related

  1. closed7.8
    Hugging Face libraries Hugging Face Transformers Downloads Custom Code Before Consent

    Supply chain · Disclosed · since 1 Sep 2026 · CVE-2026-80047

    AI
  2. closed6.5
    Hugging Face libraries CVE-2026-1839: HuggingFace Transformers Arbitrary Code Execution in Trainer

    Patch now · Disclosed · since 7 Apr 2026 · CVE-2026-1839

    AI
  3. closed7.8
    Hugging Face libraries Hugging Face Transformers Megatron GPT2 Deserialization RCE

    Patch now · Disclosed · since 23 Dec 2025 · CVE-2025-14924

    AI
  4. closed7.3
    llama.cpp CVE-2026-78147: llama.cpp RPC server vulnerable to insecure deserialization

    Patch now · Disclosed · since 23 Aug 2026 · CVE-2026-78147

    AI
  5. closed9.8
    ComfyUI + custom nodes CVE-2026-68771: ComfyUI Unsafe Deserialization in Training Dataset Node

    Patch now · Disclosed · since 31 Jul 2026 · CVE-2026-68771

    AI
  6. closed9.8
    Hugging Face libraries CVE-2026-68770: sentence-transformers local model loading remote code execution vulnerability

    Patch now · Disclosed · since 31 Jul 2026 · CVE-2026-68770

    AI