---
id: CVE-2025-6051
aliases:
  - GHSA-rcv9-qm8p-9p6j
  - PYSEC-2026-1988
title: Hugging Face Transformers library has Regular Expression Denial of Service
summary: Hugging Face Transformers library has Regular Expression Denial of Service
severity: medium
cvss: 5.3
cvssVector: 'CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L'
vendor: transformers
product: transformers
ecosystem: pip
affected:
  - transformers < 4.53.0
patched:
  - transformers 4.53.0
published: '2025-09-14'
updated: '2026-09-10'
sourceUpdated: '2026-09-10T03:50:28.694224028Z'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/GHSA-rcv9-qm8p-9p6j'
references:
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2025-6051'
  - url: 'https://github.com/huggingface/transformers/pull/38844'
  - url: >-
      https://github.com/huggingface/transformers/commit/54a02160eb030da9be18231c77791f2eb3a52216
  - url: >-
      https://github.com/huggingface/transformers/commit/ba8eaba9865618253f997784aa565b96206426f0
  - url: 'https://github.com/huggingface/transformers'
  - url: 'https://huntr.com/bounties/af929523-7b59-418a-bf55-301830b2ac9d'
tags:
  - osv
  - pip
epss: 0.00382
epssPercentile: 0.29337
ingestedAt: '2026-07-08T18:25:52.694Z'
---

## Overview

A Regular Expression Denial of Service (ReDoS) vulnerability was discovered in the Hugging Face Transformers library, specifically within the `normalize_numbers()` method of the `EnglishNormalizer` class. This vulnerability affects versions up to 4.52.4 and is fixed in version 4.53.0. The issue arises from the method's handling of numeric strings, which can be exploited using crafted input strings containing long sequences of digits, leading to excessive CPU consumption. This vulnerability impacts text-to-speech and number normalization tasks, potentially causing service disruption, resource exhaustion, and API vulnerabilities.

## Affected packages

- `transformers < 4.53.0`

## Remediation

Upgrade to a patched release:

- `transformers 4.53.0`