---
id: CVE-2025-6051
title: >-
  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
summary: >-
  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 versi…
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'
cwe:
  - CWE-1333
vendor: huggingface
product: transformers
affected:
  - transformers = 4.52.4
patched:
  - transformers 4.53.0
published: '2025-09-14'
updated: '2026-09-30'
sourceUpdated: '2026-09-30T23:10:00.237'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-6051'
references:
  - url: >-
      https://github.com/huggingface/transformers/commit/ba8eaba9865618253f997784aa565b96206426f0
    label: security@huntr.dev
  - url: 'https://huntr.com/bounties/af929523-7b59-418a-bf55-301830b2ac9d'
    label: security@huntr.dev
  - 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'
tags:
  - nvd
  - osv
  - pip
epss: 0.00382
epssPercentile: 0.31997
aliases:
  - GHSA-rcv9-qm8p-9p6j
  - PYSEC-2026-1988
ecosystem: pip
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

- `transformers = 4.52.4`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2025-6051)

Affected packages:

- `transformers < 4.53.0`

Patched in:

- `transformers 4.53.0`

Source: https://osv.dev/vulnerability/GHSA-rcv9-qm8p-9p6j