Last seen September 15, 2025

AI Security Vulnerability

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.

Technical Severity
Low severity
Lifecycle Status

RESOLVED

Sources

What Happened

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.

Why This Matters

Current evidence identifies a security issue involving Hugging Face Transformers, but does not yet support a more specific impact claim.

Recommended Action

No confirmed vendor remediation is available in the current evidence. Identify deployments of Hugging Face Transformers matching the evidenced affected versions: 4.52.4.

Exposure

My Interests Exposure

Exposure unknown

Recommended Response
Last Seen

Sep 15, 2025 00:00

Exposure reason: This incident does not currently match a technology in My Interests.

Exploitation status: UNKNOWN

Affected versions: 4.52.4

Primary entities:

Remote Code ExecutionvulnerabilityHugging Face TransformersRegular Expression DenialServicehuggingface/transformers

Timeline

  • Incident first seen
    Sep 15, 2025 00:00

    BugSkan first recorded this incident.

  • Hugging Face Transformers library has Regular Expression Denial of Service
    Sep 15, 2025 00:00

    GitHub Advisory Database · Research

Sources

Hugging Face Transformers library has Regular Expression Denial of Service

GitHub Advisory Database · Sep 15, 2025 00:00

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.

Open publisher source

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