---
id: CVE-2025-1194
aliases:
  - GHSA-fpwr-67px-3qhx
  - PYSEC-2026-1984
title: Transformers Regular Expression Denial of Service (ReDoS) vulnerability
summary: Transformers Regular Expression Denial of Service (ReDoS) vulnerability
severity: medium
cvss: 4.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L'
vendor: transformers
product: transformers
ecosystem: pip
affected:
  - transformers < 4.50.0
patched:
  - transformers 4.50.0
published: '2025-04-29'
updated: '2026-07-07'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/GHSA-fpwr-67px-3qhx'
references:
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2025-1194'
  - url: >-
      https://github.com/huggingface/transformers/commit/92c5ca9dd70de3ade2af2eb835c96215cc50e815
  - url: 'https://github.com/huggingface/transformers'
  - url: 'https://huntr.com/bounties/86f58dcd-683f-4adc-a735-849f51e9abb2'
tags:
  - osv
  - pip
epss: 0.00464
epssPercentile: 0.39426
ingestedAt: '2026-07-08T18:25:49.075Z'
---

## Overview

A Regular Expression Denial of Service (ReDoS) vulnerability was identified in the huggingface/transformers library, specifically in the file `tokenization_gpt_neox_japanese.py` of the GPT-NeoX-Japanese model. The vulnerability occurs in the SubWordJapaneseTokenizer class, where regular expressions process specially crafted inputs. The issue stems from a regex exhibiting exponential complexity under certain conditions, leading to excessive backtracking. This can result in high CPU usage and potential application downtime, effectively creating a Denial of Service (DoS) scenario. The affected version is v4.48.1 (latest).

## Affected packages

- `transformers < 4.50.0`

## Remediation

Upgrade to a patched release:

- `transformers 4.50.0`